diff --git a/lix/legacy/nix-store.cc b/lix/legacy/nix-store.cc
index 75f00e75d..afbd7c918 100644
--- a/lix/legacy/nix-store.cc
+++ b/lix/legacy/nix-store.cc
@@ -177,8 +177,12 @@ static void opAdd(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty()) throw UsageError("unknown flag");
 
-    for (auto & i : opArgs)
-        cout << fmt("%s\n", store->printStorePath(store->addToStore(std::string(baseNameOf(i)), i)));
+    for (auto & i : opArgs) {
+        cout << fmt(
+            "%s\n",
+            store->printStorePath(aio.blockOn(store->addToStore(std::string(baseNameOf(i)), i)))
+        );
+    }
 }
 
 
@@ -995,7 +999,7 @@ static void opServe(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
                 SizedSource sizedSource(in, info.narSize);
 
-                store->addToStore(info, sizedSource, NoRepair, NoCheckSigs);
+                aio.blockOn(store->addToStore(info, sizedSource, NoRepair, NoCheckSigs));
 
                 // consume all the data that has been sent before continuing.
                 sizedSource.drainAll();
diff --git a/lix/libcmd/cmd-profiles.cc b/lix/libcmd/cmd-profiles.cc
index c60ad96fb..438556847 100644
--- a/lix/libcmd/cmd-profiles.cc
+++ b/lix/libcmd/cmd-profiles.cc
@@ -267,7 +267,7 @@ try {
     info.narSize = sink.s.size();
 
     StringSource source(sink.s);
-    store->addToStore(info, source);
+    TRY_AWAIT(store->addToStore(info, source));
 
     co_return std::move(info.path);
 } catch (...) {
diff --git a/lix/libfetchers/fetch-to-store.cc b/lix/libfetchers/fetch-to-store.cc
index 09ae5ff7c..7affb9ddd 100644
--- a/lix/libfetchers/fetch-to-store.cc
+++ b/lix/libfetchers/fetch-to-store.cc
@@ -19,7 +19,7 @@ try {
     co_return
         settings.readOnlyMode
         ? store.computeStorePathForPath(name, path.canonical().abs(), method, HashType::SHA256, filter2).first
-        : store.addToStore(name, path.canonical().abs(), method, HashType::SHA256, filter2, repair);
+        : TRY_AWAIT(store.addToStore(name, path.canonical().abs(), method, HashType::SHA256, filter2, repair));
 } catch (...) {
     co_return result::current_exception();
 }
diff --git a/lix/libfetchers/git.cc b/lix/libfetchers/git.cc
index ec9285f67..1c1d54674 100644
--- a/lix/libfetchers/git.cc
+++ b/lix/libfetchers/git.cc
@@ -207,8 +207,8 @@ WorkdirInfo getWorkdirInfo(const Input & input, const Path & workdir)
     return WorkdirInfo { .clean = clean, .hasHead = hasHead };
 }
 
-std::pair<StorePath, Input> fetchFromWorkdir(ref<Store> store, Input & input, const Path & workdir, const WorkdirInfo & workdirInfo)
-{
+static kj::Promise<Result<std::pair<StorePath, Input>>> fetchFromWorkdir(ref<Store> store, Input & input, const Path & workdir, const WorkdirInfo & workdirInfo)
+try {
     const bool submodules = maybeGetBoolAttr(input.attrs, "submodules").value_or(false);
     auto gitDir = ".git";
 
@@ -242,7 +242,9 @@ std::pair<StorePath, Input> fetchFromWorkdir(ref<Store> store, Input & input, co
         return files.count(file);
     };
 
-    auto storePath = store->addToStore(input.getName(), actualPath, FileIngestionMethod::Recursive, HashType::SHA256, filter);
+    auto storePath = TRY_AWAIT(store->addToStore(
+        input.getName(), actualPath, FileIngestionMethod::Recursive, HashType::SHA256, filter
+    ));
 
     // FIXME: maybe we should use the timestamp of the last
     // modified dirty file?
@@ -257,7 +259,9 @@ std::pair<StorePath, Input> fetchFromWorkdir(ref<Store> store, Input & input, co
             runProgram("git", true, { "-C", actualPath, "--git-dir", gitDir, "rev-parse", "--verify", "--short", "HEAD" })) + "-dirty");
     }
 
-    return {std::move(storePath), input};
+    co_return {std::move(storePath), input};
+} catch (...) {
+    co_return result::current_exception();
 }
 }  // end namespace
 
@@ -503,7 +507,7 @@ struct GitInputScheme : InputScheme
         if (!input.getRef() && !input.getRev() && isLocal) {
             auto workdirInfo = getWorkdirInfo(input, actualUrl);
             if (!workdirInfo.clean) {
-                co_return fetchFromWorkdir(store, input, actualUrl, workdirInfo);
+                co_return TRY_AWAIT(fetchFromWorkdir(store, input, actualUrl, workdirInfo));
             }
         }
 
@@ -766,7 +770,9 @@ struct GitInputScheme : InputScheme
             unpackTarfile(*proc.getStdout(), tmpDir);
         }
 
-        auto storePath = store->addToStore(name, tmpDir, FileIngestionMethod::Recursive, HashType::SHA256, filter);
+        auto storePath = TRY_AWAIT(store->addToStore(
+            name, tmpDir, FileIngestionMethod::Recursive, HashType::SHA256, filter
+        ));
 
         auto lastModified = std::stoull(runProgram("git", true, { "-C", repoDir, "--git-dir", gitDir, "log", "-1", "--format=%ct", "--no-show-signature", input.getRev()->gitRev() }));
 
diff --git a/lix/libfetchers/mercurial.cc b/lix/libfetchers/mercurial.cc
index 623cf9d36..d70a075e5 100644
--- a/lix/libfetchers/mercurial.cc
+++ b/lix/libfetchers/mercurial.cc
@@ -202,7 +202,13 @@ struct MercurialInputScheme : InputScheme
                     return files.count(file);
                 };
 
-                auto storePath = store->addToStore(input.getName(), actualPath, FileIngestionMethod::Recursive, HashType::SHA256, filter);
+                auto storePath = TRY_AWAIT(store->addToStore(
+                    input.getName(),
+                    actualPath,
+                    FileIngestionMethod::Recursive,
+                    HashType::SHA256,
+                    filter
+                ));
 
                 co_return {std::move(storePath), input};
             }
@@ -313,7 +319,7 @@ struct MercurialInputScheme : InputScheme
 
         deletePath(tmpDir + "/.hg_archival.txt");
 
-        auto storePath = store->addToStore(name, tmpDir);
+        auto storePath = TRY_AWAIT(store->addToStore(name, tmpDir));
 
         Attrs infoAttrs({
             {"rev", input.getRev()->gitRev()},
diff --git a/lix/libfetchers/tarball.cc b/lix/libfetchers/tarball.cc
index 201552b77..c9afa6cd8 100644
--- a/lix/libfetchers/tarball.cc
+++ b/lix/libfetchers/tarball.cc
@@ -89,7 +89,7 @@ try {
         };
         info.narSize = sink.s.size();
         auto source = StringSource { sink.s };
-        store->addToStore(info, source, NoRepair, NoCheckSigs);
+        TRY_AWAIT(store->addToStore(info, source, NoRepair, NoCheckSigs));
         storePath = std::move(info.path);
     }
 
@@ -161,7 +161,14 @@ try {
             throw nix::Error("tarball '%s' contains an unexpected number of top-level files", url);
         auto topDir = tmpDir + "/" + members.begin()->name;
         lastModified = lstat(topDir).st_mtime;
-        unpackedStorePath = store->addToStore(name, topDir, FileIngestionMethod::Recursive, HashType::SHA256, defaultPathFilter, NoRepair);
+        unpackedStorePath = TRY_AWAIT(store->addToStore(
+            name,
+            topDir,
+            FileIngestionMethod::Recursive,
+            HashType::SHA256,
+            defaultPathFilter,
+            NoRepair
+        ));
     }
 
     Attrs infoAttrs({
diff --git a/lix/libstore/binary-cache-store.cc b/lix/libstore/binary-cache-store.cc
index a9301df3c..ccdd28cd0 100644
--- a/lix/libstore/binary-cache-store.cc
+++ b/lix/libstore/binary-cache-store.cc
@@ -4,6 +4,7 @@
 #include "lix/libstore/derivations.hh"
 #include "lix/libstore/fs-accessor.hh"
 #include "lix/libstore/nar-info.hh"
+#include "lix/libutil/result.hh"
 #include "lix/libutil/sync.hh"
 #include "lix/libstore/remote-fs-accessor.hh"
 #include "lix/libstore/nar-info-disk-cache.hh" // IWYU pragma: keep
@@ -255,13 +256,13 @@ ref<const ValidPathInfo> BinaryCacheStore::addToStoreCommon(
     return narInfo;
 }
 
-void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource,
+kj::Promise<Result<void>> BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource,
     RepairFlag repair, CheckSigsFlag checkSigs)
-{
+try {
     if (!repair && isValidPath(info.path)) {
         // FIXME: copyNAR -> null sink
         narSource.drain();
-        return;
+        co_return result::success();
     }
 
     addToStoreCommon(narSource, repair, checkSigs, {[&](HashResult nar) {
@@ -271,6 +272,9 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource
         // assert(info.narSize == nar.second);
         return info;
     }});
+    co_return result::success();
+} catch (...) {
+    co_return result::current_exception();
 }
 
 StorePath BinaryCacheStore::addToStoreFromDump(Source & dump, std::string_view name,
@@ -365,7 +369,7 @@ std::shared_ptr<const ValidPathInfo> BinaryCacheStore::queryPathInfoUncached(con
     return std::make_shared<NarInfo>(*this, *data, narInfoFile);
 }
 
-StorePath BinaryCacheStore::addToStore(
+kj::Promise<Result<StorePath>> BinaryCacheStore::addToStore(
     std::string_view name,
     const Path & srcPath,
     FileIngestionMethod method,
@@ -373,7 +377,7 @@ StorePath BinaryCacheStore::addToStore(
     PathFilter & filter,
     RepairFlag repair,
     const StorePathSet & references)
-{
+try {
     /* FIXME: Make BinaryCacheStore::addToStoreCommon support
        non-recursive+sha256 so we can just use the default
        implementation of this method in terms of addToStoreFromDump. */
@@ -387,7 +391,7 @@ StorePath BinaryCacheStore::addToStore(
     auto h = sink.finish().first;
 
     auto source = GeneratorSource{dumpPath(srcPath, filter)};
-    return addToStoreCommon(source, repair, CheckSigs, [&](HashResult nar) {
+    co_return addToStoreCommon(source, repair, CheckSigs, [&](HashResult nar) {
         ValidPathInfo info {
             *this,
             name,
@@ -405,6 +409,8 @@ StorePath BinaryCacheStore::addToStore(
         info.narSize = nar.second;
         return info;
     })->path;
+} catch (...) {
+    co_return result::current_exception();
 }
 
 StorePath BinaryCacheStore::addTextToStore(
diff --git a/lix/libstore/binary-cache-store.hh b/lix/libstore/binary-cache-store.hh
index c251ca108..8381e24e1 100644
--- a/lix/libstore/binary-cache-store.hh
+++ b/lix/libstore/binary-cache-store.hh
@@ -113,13 +113,13 @@ public:
 
     std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override;
 
-    void addToStore(const ValidPathInfo & info, Source & narSource,
+    kj::Promise<Result<void>> addToStore(const ValidPathInfo & info, Source & narSource,
         RepairFlag repair, CheckSigsFlag checkSigs) override;
 
     StorePath addToStoreFromDump(Source & dump, std::string_view name,
         FileIngestionMethod method, HashType hashAlgo, RepairFlag repair, const StorePathSet & references) override;
 
-    StorePath addToStore(
+    kj::Promise<Result<StorePath>> addToStore(
         std::string_view name,
         const Path & srcPath,
         FileIngestionMethod method,
diff --git a/lix/libstore/build/local-derivation-goal.cc b/lix/libstore/build/local-derivation-goal.cc
index dbd8bf4f9..964667ca7 100644
--- a/lix/libstore/build/local-derivation-goal.cc
+++ b/lix/libstore/build/local-derivation-goal.cc
@@ -1049,7 +1049,7 @@ struct RestrictedStore : public virtual IndirectRootStore, public virtual GcStor
     std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override
     { throw Error("queryPathFromHashPart"); }
 
-    StorePath addToStore(
+    kj::Promise<Result<StorePath>> addToStore(
         std::string_view name,
         const Path & srcPath,
         FileIngestionMethod method,
@@ -1057,13 +1057,16 @@ struct RestrictedStore : public virtual IndirectRootStore, public virtual GcStor
         PathFilter & filter,
         RepairFlag repair,
         const StorePathSet & references) override
-    { throw Error("addToStore"); }
+    try { throw Error("addToStore"); } catch (...) { return {result::current_exception()}; }
 
-    void addToStore(const ValidPathInfo & info, Source & narSource,
+    kj::Promise<Result<void>> addToStore(const ValidPathInfo & info, Source & narSource,
         RepairFlag repair = NoRepair, CheckSigsFlag checkSigs = CheckSigs) override
-    {
-        next->addToStore(info, narSource, repair, checkSigs);
+    try {
+        TRY_AWAIT(next->addToStore(info, narSource, repair, checkSigs));
         goal.addDependency(info.path);
+        co_return result::success();
+    } catch (...) {
+        co_return result::current_exception();
     }
 
     StorePath addTextToStore(
diff --git a/lix/libstore/build/substitution-goal.cc b/lix/libstore/build/substitution-goal.cc
index 55721ca42..34f5294af 100644
--- a/lix/libstore/build/substitution-goal.cc
+++ b/lix/libstore/build/substitution-goal.cc
@@ -210,6 +210,7 @@ try {
     outPipe = kj::mv(pipe.fulfiller);
 
     thr = std::async(std::launch::async, [this]() {
+        AsyncIoRoot aio;
         /* Wake up the worker loop when we're done. */
         Finally updateStats([this]() { outPipe->fulfill(); });
 
@@ -221,6 +222,7 @@ try {
             PushActivity pact(act.id);
 
             copyStorePath(
+                aio,
                 *sub,
                 worker.store,
                 fetchPath,
diff --git a/lix/libstore/daemon.cc b/lix/libstore/daemon.cc
index c63c21e04..ef779a630 100644
--- a/lix/libstore/daemon.cc
+++ b/lix/libstore/daemon.cc
@@ -900,8 +900,8 @@ static void performOp(AsyncIoRoot & aio, TunnelLogger * logger, ref<Store> store
             logger->startWork();
             {
                 FramedSource source(from);
-                store->addToStore(info, source, (RepairFlag) repair,
-                    dontCheckSigs ? NoCheckSigs : CheckSigs);
+                aio.blockOn(store->addToStore(info, source, (RepairFlag) repair,
+                    dontCheckSigs ? NoCheckSigs : CheckSigs));
             }
             logger->stopWork();
         }
@@ -913,8 +913,8 @@ static void performOp(AsyncIoRoot & aio, TunnelLogger * logger, ref<Store> store
             logger->startWork();
 
             // FIXME: race if addToStore doesn't read source?
-            store->addToStore(info, *source, (RepairFlag) repair,
-                dontCheckSigs ? NoCheckSigs : CheckSigs);
+            aio.blockOn(store->addToStore(info, *source, (RepairFlag) repair,
+                dontCheckSigs ? NoCheckSigs : CheckSigs));
 
             logger->stopWork();
         }
diff --git a/lix/libstore/dummy-store.cc b/lix/libstore/dummy-store.cc
index 38da8110e..33637ccbb 100644
--- a/lix/libstore/dummy-store.cc
+++ b/lix/libstore/dummy-store.cc
@@ -54,9 +54,9 @@ struct DummyStore final : public Store
     std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override
     { unsupported("queryPathFromHashPart"); }
 
-    void addToStore(const ValidPathInfo & info, Source & source,
+    kj::Promise<Result<void>> addToStore(const ValidPathInfo & info, Source & source,
         RepairFlag repair, CheckSigsFlag checkSigs) override
-    { unsupported("addToStore"); }
+    try { unsupported("addToStore"); } catch (...) { return {result::current_exception()}; }
 
     StorePath addTextToStore(
         std::string_view name,
diff --git a/lix/libstore/export-import.cc b/lix/libstore/export-import.cc
index 39e666a6d..1eb70bee2 100644
--- a/lix/libstore/export-import.cc
+++ b/lix/libstore/export-import.cc
@@ -86,7 +86,7 @@ try {
 
         // Can't use underlying source, which would have been exhausted
         auto source = StringSource(saved.s);
-        addToStore(info, source, NoRepair, checkSigs);
+        TRY_AWAIT(addToStore(info, source, NoRepair, checkSigs));
 
         res.push_back(info.path);
     }
diff --git a/lix/libstore/legacy-ssh-store.cc b/lix/libstore/legacy-ssh-store.cc
index 0f4be8064..5f96c9f8e 100644
--- a/lix/libstore/legacy-ssh-store.cc
+++ b/lix/libstore/legacy-ssh-store.cc
@@ -9,6 +9,7 @@
 #include "lix/libstore/path-with-outputs.hh"
 #include "lix/libstore/ssh.hh"
 #include "lix/libstore/ssh-store.hh"
+#include "lix/libutil/result.hh"
 #include "lix/libutil/strings.hh"
 #include "lix/libstore/derivations.hh"
 
@@ -185,9 +186,9 @@ struct LegacySSHStore final : public Store
         return info;
     }
 
-    void addToStore(const ValidPathInfo & info, Source & source,
+    kj::Promise<Result<void>> addToStore(const ValidPathInfo & info, Source & source,
         RepairFlag repair, CheckSigsFlag checkSigs) override
-    {
+    try {
         debug("adding path '%s' to remote host '%s'", printStorePath(info.path), host);
 
         auto conn(connections->get());
@@ -239,6 +240,9 @@ struct LegacySSHStore final : public Store
 
         if (readInt(conn->from) != 1)
             throw Error("failed to add path '%s' to remote host '%s'", printStorePath(info.path), host);
+        co_return result::success();
+    } catch (...) {
+        co_return result::current_exception();
     }
 
     box_ptr<Source> narFromPath(const StorePath & path) override
@@ -255,7 +259,7 @@ struct LegacySSHStore final : public Store
     std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override
     { unsupported("queryPathFromHashPart"); }
 
-    StorePath addToStore(
+    kj::Promise<Result<StorePath>> addToStore(
         std::string_view name,
         const Path & srcPath,
         FileIngestionMethod method,
@@ -263,7 +267,7 @@ struct LegacySSHStore final : public Store
         PathFilter & filter,
         RepairFlag repair,
         const StorePathSet & references) override
-    { unsupported("addToStore"); }
+    try { unsupported("addToStore"); } catch (...) { return {result::current_exception()}; }
 
     StorePath addTextToStore(
         std::string_view name,
diff --git a/lix/libstore/local-store.cc b/lix/libstore/local-store.cc
index b206e2ffa..95f5f986a 100644
--- a/lix/libstore/local-store.cc
+++ b/lix/libstore/local-store.cc
@@ -1195,9 +1195,9 @@ bool LocalStore::realisationIsUntrusted(const Realisation & realisation)
     return config_.requireSigs && !realisation.checkSignatures(getPublicKeys());
 }
 
-void LocalStore::addToStore(const ValidPathInfo & info, Source & source,
+kj::Promise<Result<void>> LocalStore::addToStore(const ValidPathInfo & info, Source & source,
     RepairFlag repair, CheckSigsFlag checkSigs)
-{
+try {
     if (checkSigs && pathInfoIsUntrusted(info))
         throw Error("cannot add path '%s' because it lacks a signature by a trusted key", printStorePath(info.path));
 
@@ -1275,6 +1275,9 @@ void LocalStore::addToStore(const ValidPathInfo & info, Source & source,
             registerValidPath(info);
         }
     }
+    co_return result::success();
+} catch (...) {
+    co_return result::current_exception();
 }
 
 
diff --git a/lix/libstore/local-store.hh b/lix/libstore/local-store.hh
index 57dace264..bab56600e 100644
--- a/lix/libstore/local-store.hh
+++ b/lix/libstore/local-store.hh
@@ -204,7 +204,7 @@ public:
     bool pathInfoIsUntrusted(const ValidPathInfo &) override;
     bool realisationIsUntrusted(const Realisation & ) override;
 
-    void addToStore(const ValidPathInfo & info, Source & source,
+    kj::Promise<Result<void>> addToStore(const ValidPathInfo & info, Source & source,
         RepairFlag repair, CheckSigsFlag checkSigs) override;
 
     StorePath addToStoreFromDump(Source & dump, std::string_view name,
diff --git a/lix/libstore/make-content-addressed.cc b/lix/libstore/make-content-addressed.cc
index baac4ab32..bf5f5e041 100644
--- a/lix/libstore/make-content-addressed.cc
+++ b/lix/libstore/make-content-addressed.cc
@@ -69,7 +69,7 @@ try {
         info.narSize = sink.s.size();
 
         StringSource source(rewritten);
-        dstStore.addToStore(info, source);
+        TRY_AWAIT(dstStore.addToStore(info, source));
 
         remappings.insert_or_assign(std::move(path), std::move(info.path));
     }
diff --git a/lix/libstore/remote-store.cc b/lix/libstore/remote-store.cc
index b512be79b..057b13c58 100644
--- a/lix/libstore/remote-store.cc
+++ b/lix/libstore/remote-store.cc
@@ -465,9 +465,9 @@ StorePath RemoteStore::addToStoreFromDump(Source & dump, std::string_view name,
 }
 
 
-void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
+kj::Promise<Result<void>> RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
     RepairFlag repair, CheckSigsFlag checkSigs)
-{
+try {
     auto conn(getConnection());
 
     conn->to << WorkerProto::Op::AddToStoreNar
@@ -486,6 +486,9 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
     } else {
         conn.processStderr(0, &source);
     }
+    co_return result::success();
+} catch (...) {
+    co_return result::current_exception();
 }
 
 
diff --git a/lix/libstore/remote-store.hh b/lix/libstore/remote-store.hh
index f4285a8ef..2faa29b11 100644
--- a/lix/libstore/remote-store.hh
+++ b/lix/libstore/remote-store.hh
@@ -88,7 +88,7 @@ public:
     StorePath addToStoreFromDump(Source & dump, std::string_view name,
         FileIngestionMethod method = FileIngestionMethod::Recursive, HashType hashAlgo = HashType::SHA256, RepairFlag repair = NoRepair, const StorePathSet & references = StorePathSet()) override;
 
-    void addToStore(const ValidPathInfo & info, Source & nar,
+    kj::Promise<Result<void>> addToStore(const ValidPathInfo & info, Source & nar,
         RepairFlag repair, CheckSigsFlag checkSigs) override;
 
     kj::Promise<Result<void>> addMultipleToStore(
diff --git a/lix/libstore/store-api.cc b/lix/libstore/store-api.cc
index 28f8c0bf2..b130ff26d 100644
--- a/lix/libstore/store-api.cc
+++ b/lix/libstore/store-api.cc
@@ -269,7 +269,7 @@ StorePath Store::computeStorePathForText(
 }
 
 
-StorePath Store::addToStore(
+kj::Promise<Result<StorePath>> Store::addToStore(
     std::string_view name,
     const Path & _srcPath,
     FileIngestionMethod method,
@@ -277,13 +277,15 @@ StorePath Store::addToStore(
     PathFilter & filter,
     RepairFlag repair,
     const StorePathSet & references)
-{
+try {
     Path srcPath(absPath(_srcPath));
     auto source = GeneratorSource{
         method == FileIngestionMethod::Recursive ? dumpPath(srcPath, filter).decay()
                                                  : readFileSource(srcPath)
     };
-    return addToStoreFromDump(source, name, method, hashAlgo, repair, references);
+    co_return addToStoreFromDump(source, name, method, hashAlgo, repair, references);
+} catch (...) {
+    co_return result::current_exception();
 }
 
 kj::Promise<Result<void>> Store::addMultipleToStore(
@@ -313,7 +315,7 @@ try {
     processGraph<StorePath>("addMultipleToStore pool",
         storePathsToAdd,
 
-        [&](const StorePath & path) {
+        [&](AsyncIoRoot & aio, const StorePath & path) {
 
             auto & [info, _] = *infosMap.at(path);
 
@@ -329,7 +331,7 @@ try {
             return info.references;
         },
 
-        [&](const StorePath & path) {
+        [&](AsyncIoRoot & aio, const StorePath & path) {
             checkInterrupt();
 
             auto & [info_, source_] = *infosMap.at(path);
@@ -347,7 +349,7 @@ try {
                 MaintainCount<decltype(nrRunning)> mc(nrRunning);
                 showProgress();
                 try {
-                    addToStore(info, *source, repair, checkSigs);
+                    aio.blockOn(addToStore(info, *source, repair, checkSigs));
                 } catch (Error & e) {
                     nrFailed++;
                     if (!settings.keepGoing)
@@ -380,7 +382,7 @@ try {
             WorkerProto::ReadConn {source, remoteVersion}
         );
         info.ultimate = false;
-        addToStore(info, source, repair, checkSigs);
+        TRY_AWAIT(addToStore(info, source, repair, checkSigs));
     }
     co_return result::success();
 } catch (...) {
@@ -513,7 +515,7 @@ try {
 
     if (!isValidPath(info.path)) {
         auto source = GeneratorSource{dumpPath(srcPath)};
-        addToStore(info, source);
+        TRY_AWAIT(addToStore(info, source));
     }
 
     co_return info;
@@ -1091,6 +1093,7 @@ static std::string makeCopyPathMessage(
 static constexpr unsigned PATH_COPY_BUFSIZE = 65536;
 
 void copyStorePath(
+    AsyncIoRoot & aio,
     Store & srcStore,
     Store & dstStore,
     const StorePath & storePath,
@@ -1147,7 +1150,7 @@ void copyStorePath(
         }(act, info, srcStore, storePath)
     };
 
-    dstStore.addToStore(*info, source, repair, checkSigs);
+    aio.blockOn(dstStore.addToStore(*info, source, repair, checkSigs));
 }
 
 
diff --git a/lix/libstore/store-api.hh b/lix/libstore/store-api.hh
index 563281ea1..5175d0de8 100644
--- a/lix/libstore/store-api.hh
+++ b/lix/libstore/store-api.hh
@@ -1,6 +1,7 @@
 #pragma once
 ///@file
 
+#include "lix/libutil/async.hh"
 #include "lix/libutil/logging.hh"
 #include "lix/libstore/nar-info.hh"
 #include "lix/libstore/realisation.hh"
@@ -495,7 +496,7 @@ public:
     /**
      * Import a path into the store.
      */
-    virtual void addToStore(const ValidPathInfo & info, Source & narSource,
+    virtual kj::Promise<Result<void>> addToStore(const ValidPathInfo & info, Source & narSource,
         RepairFlag repair = NoRepair, CheckSigsFlag checkSigs = CheckSigs) = 0;
 
     /**
@@ -526,7 +527,7 @@ public:
      * @param filter This function can be used to exclude files (see
      * libutil/archive.hh).
      */
-    virtual StorePath addToStore(
+    virtual kj::Promise<Result<StorePath>> addToStore(
         std::string_view name,
         const Path & srcPath,
         FileIngestionMethod method = FileIngestionMethod::Recursive,
@@ -907,6 +908,7 @@ protected:
  * Copy a path from one store to another.
  */
 void copyStorePath(
+    AsyncIoRoot & aio,
     Store & srcStore,
     Store & dstStore,
     const StorePath & storePath,
diff --git a/lix/nix/add-to-store.cc b/lix/nix/add-to-store.cc
index e93b1f9c9..ca4bfc04d 100644
--- a/lix/nix/add-to-store.cc
+++ b/lix/nix/add-to-store.cc
@@ -55,7 +55,7 @@ struct CmdAddToStore : MixDryRun, StoreCommand
 
         if (!dryRun) {
             auto source = StringSource(sink.s);
-            store->addToStore(info, source);
+            aio().blockOn(store->addToStore(info, source));
         }
 
         logger->cout("%s", store->printStorePath(info.path));
diff --git a/perl/lib/Nix/Store.xs b/perl/lib/Nix/Store.xs
index 20875e019..65d0b93db 100644
--- a/perl/lib/Nix/Store.xs
+++ b/perl/lib/Nix/Store.xs
@@ -292,7 +292,7 @@ SV * addToStore(char * srcPath, int recursive, char * algo)
     PPCODE:
         try {
             auto method = recursive ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
-            auto path = store()->addToStore(std::string(baseNameOf(srcPath)), srcPath, method, parseHashType(algo));
+            auto path = aio().blockOn(store()->addToStore(std::string(baseNameOf(srcPath)), srcPath, method, parseHashType(algo)));
             XPUSHs(sv_2mortal(newSVpv(store()->printStorePath(path).c_str(), 0)));
         } catch (Error & e) {
             croak("%s", e.what());