diff --git a/lix/legacy/nix-build.cc b/lix/legacy/nix-build.cc
index 1a4cce8f5..1d0dd3d60 100644
--- a/lix/legacy/nix-build.cc
+++ b/lix/legacy/nix-build.cc
@@ -612,7 +612,7 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
             if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>()) {
                 std::string symlink = drvPrefix;
                 if (outputName != "out") symlink += "-" + outputName;
-                store2->addPermRoot(outputPath, absPath(symlink));
+                aio.blockOn(store2->addPermRoot(outputPath, absPath(symlink)));
             }
 
             outPaths.push_back(outputPath);
diff --git a/lix/legacy/nix-instantiate.cc b/lix/legacy/nix-instantiate.cc
index a164f3aba..f8db06ef9 100644
--- a/lix/legacy/nix-instantiate.cc
+++ b/lix/legacy/nix-instantiate.cc
@@ -80,7 +80,7 @@ void processExpr(EvalState & state, const Strings & attrPaths,
                     if (++rootNr > 1) rootName += "-" + std::to_string(rootNr);
                     auto store2 = state.ctx.store.dynamic_pointer_cast<LocalFSStore>();
                     if (store2)
-                        drvPathS = store2->addPermRoot(drvPath, rootName);
+                        drvPathS = state.aio.blockOn(store2->addPermRoot(drvPath, rootName));
                 }
                 std::cout << fmt("%s%s\n", drvPathS, (outputName != "out" ? "!" + outputName : ""));
             }
diff --git a/lix/legacy/nix-store.cc b/lix/legacy/nix-store.cc
index f1ce0298e..742a2db0b 100644
--- a/lix/legacy/nix-store.cc
+++ b/lix/legacy/nix-store.cc
@@ -92,7 +92,7 @@ try {
                     Path rootName = gcRoot;
                     if (rootNr > 1) rootName += "-" + std::to_string(rootNr);
                     if (i->first != "out") rootName += "-" + i->first;
-                    retPath = store2->addPermRoot(outPath, rootName);
+                    retPath = TRY_AWAIT(store2->addPermRoot(outPath, rootName));
                 }
             }
             outputs.insert(retPath);
@@ -111,7 +111,7 @@ try {
                 Path rootName = gcRoot;
                 rootNr++;
                 if (rootNr > 1) rootName += "-" + std::to_string(rootNr);
-                co_return PathSet{store2->addPermRoot(path.path, rootName)};
+                co_return PathSet{TRY_AWAIT(store2->addPermRoot(path.path, rootName))};
             }
         }
         co_return PathSet{store->printStorePath(path.path)};
diff --git a/lix/libcmd/repl.cc b/lix/libcmd/repl.cc
index 2925fe3bd..a9ec776d2 100644
--- a/lix/libcmd/repl.cc
+++ b/lix/libcmd/repl.cc
@@ -782,7 +782,7 @@ ProcessLineResult NixRepl::processLine(std::string line)
                 auto localStore = evaluator.store.dynamic_pointer_cast<LocalFSStore>();
                 if (localStore && command == ":bl") {
                     std::string symlink = "repl-result-" + outputName;
-                    localStore->addPermRoot(outputPath, absPath(symlink));
+                    state.aio.blockOn(localStore->addPermRoot(outputPath, absPath(symlink)));
                     logger->cout("  ./%s -> %s", symlink, evaluator.store->printStorePath(outputPath));
                 } else {
                     logger->cout("  %s -> %s", outputName, evaluator.store->printStorePath(outputPath));
diff --git a/lix/libfetchers/registry.cc b/lix/libfetchers/registry.cc
index 732d87421..bb6bc4338 100644
--- a/lix/libfetchers/registry.cc
+++ b/lix/libfetchers/registry.cc
@@ -184,8 +184,11 @@ try {
                 );
 
                 auto storePath = downloadFile(store, path, "flake-registry.json", false).storePath;
-                if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>())
-                    store2->addPermRoot(storePath, getCacheDir() + "/nix/flake-registry.json");
+                if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>()) {
+                    TRY_AWAIT(
+                        store2->addPermRoot(storePath, getCacheDir() + "/nix/flake-registry.json")
+                    );
+                }
                 path = store->toRealPath(storePath);
             }
 
diff --git a/lix/libstore/gc.cc b/lix/libstore/gc.cc
index e5636a994..c8c78b5f4 100644
--- a/lix/libstore/gc.cc
+++ b/lix/libstore/gc.cc
@@ -51,8 +51,8 @@ void LocalStore::addIndirectRoot(const Path & path)
 }
 
 
-Path IndirectRootStore::addPermRoot(const StorePath & storePath, const Path & _gcRoot)
-{
+kj::Promise<Result<Path>> IndirectRootStore::addPermRoot(const StorePath & storePath, const Path & _gcRoot)
+try {
     Path gcRoot(canonPath(_gcRoot));
 
     if (isInStore(gcRoot))
@@ -73,7 +73,9 @@ Path IndirectRootStore::addPermRoot(const StorePath & storePath, const Path & _g
     makeSymlink(gcRoot, printStorePath(storePath));
     addIndirectRoot(gcRoot);
 
-    return gcRoot;
+    co_return gcRoot;
+} catch (...) {
+    co_return result::current_exception();
 }
 
 
diff --git a/lix/libstore/indirect-root-store.hh b/lix/libstore/indirect-root-store.hh
index 9bfa1f68b..26b023efd 100644
--- a/lix/libstore/indirect-root-store.hh
+++ b/lix/libstore/indirect-root-store.hh
@@ -31,7 +31,8 @@ struct IndirectRootStore : public virtual LocalFSStore
      * The implementation of this method is concrete, but it delegates
      * to `addIndirectRoot()` which is abstract.
      */
-    Path addPermRoot(const StorePath & storePath, const Path & gcRoot) override final;
+    kj::Promise<Result<Path>>
+    addPermRoot(const StorePath & storePath, const Path & gcRoot) override final;
 
     /**
      * Add an indirect root, which is a weak reference to the
diff --git a/lix/libstore/local-fs-store.hh b/lix/libstore/local-fs-store.hh
index b9ad4480b..d31264b47 100644
--- a/lix/libstore/local-fs-store.hh
+++ b/lix/libstore/local-fs-store.hh
@@ -59,7 +59,8 @@ public:
      * How the permanent GC root corresponding to this symlink is
      * managed is implementation-specific.
      */
-    virtual Path addPermRoot(const StorePath & storePath, const Path & gcRoot) = 0;
+    virtual kj::Promise<Result<Path>>
+    addPermRoot(const StorePath & storePath, const Path & gcRoot) = 0;
 
     virtual Path getRealStoreDir() { return config().realStoreDir; }
 
diff --git a/lix/libstore/profiles.cc b/lix/libstore/profiles.cc
index 675b46bbf..f4f74b6d3 100644
--- a/lix/libstore/profiles.cc
+++ b/lix/libstore/profiles.cc
@@ -1,5 +1,6 @@
 #include "lix/libstore/profiles.hh"
 #include "lix/libstore/local-fs-store.hh"
+#include "lix/libutil/async.hh"
 #include "lix/libutil/users.hh"
 #include "lix/libutil/strings.hh"
 
@@ -102,7 +103,7 @@ try {
        view).  If we didn't do it this way, the GC might remove the
        user environment etc. we've just built. */
     Path generation = makeName(profile, num + 1);
-    store.addPermRoot(outPath, generation);
+    TRY_AWAIT(store.addPermRoot(outPath, generation));
 
     co_return generation;
 } catch (...) {
diff --git a/lix/nix/build.cc b/lix/nix/build.cc
index 384369e56..7602f719f 100644
--- a/lix/nix/build.cc
+++ b/lix/nix/build.cc
@@ -3,6 +3,7 @@
 #include "lix/libmain/shared.hh"
 #include "lix/libstore/store-api.hh"
 #include "lix/libstore/local-fs-store.hh"
+#include "lix/libutil/async.hh"
 
 #include <nlohmann/json.hpp>
 
@@ -42,7 +43,12 @@ static nlohmann::json builtPathsWithResultToJSON(const std::vector<BuiltPathWith
 }
 
 // TODO deduplicate with other code also setting such out links.
-static void createOutLinks(const Path& outLink, const std::vector<BuiltPathWithResult>& buildables, LocalFSStore& store2)
+static void createOutLinks(
+    AsyncIoRoot & aio,
+    const Path & outLink,
+    const std::vector<BuiltPathWithResult> & buildables,
+    LocalFSStore & store2
+)
 {
     for (const auto & [_i, buildable] : enumerate(buildables)) {
         auto i = _i;
@@ -50,14 +56,14 @@ static void createOutLinks(const Path& outLink, const std::vector<BuiltPathWithR
             [&](const BuiltPath::Opaque & bo) {
                 std::string symlink = outLink;
                 if (i) symlink += fmt("-%d", i);
-                store2.addPermRoot(bo.path, absPath(symlink));
+                aio.blockOn(store2.addPermRoot(bo.path, absPath(symlink)));
             },
             [&](const BuiltPath::Built & bfd) {
                 for (auto & output : bfd.outputs) {
                     std::string symlink = outLink;
                     if (i) symlink += fmt("-%d", i);
                     if (output.first != "out") symlink += fmt("-%s", output.first);
-                    store2.addPermRoot(output.second, absPath(symlink));
+                    aio.blockOn(store2.addPermRoot(output.second, absPath(symlink)));
                 }
             },
         }, buildable.path.raw());
@@ -141,7 +147,7 @@ struct CmdBuild : InstallablesCommand, MixDryRun, MixJSON, MixProfile
 
         if (outLink != "")
             if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>())
-                createOutLinks(outLink, buildables, *store2);
+                createOutLinks(aio(), outLink, buildables, *store2);
 
         if (printOutputPaths) {
             logger->pause();
diff --git a/lix/nix/bundle.cc b/lix/nix/bundle.cc
index 79bcc7112..261cd8416 100644
--- a/lix/nix/bundle.cc
+++ b/lix/nix/bundle.cc
@@ -125,7 +125,9 @@ struct CmdBundle : InstallableCommand
         }
 
         // TODO: will crash if not a localFSStore?
-        store.dynamic_pointer_cast<LocalFSStore>()->addPermRoot(outPath, absPath(*outLink));
+        aio().blockOn(
+            store.dynamic_pointer_cast<LocalFSStore>()->addPermRoot(outPath, absPath(*outLink))
+        );
     }
 };