diff --git a/lix/legacy/nix-store.cc b/lix/legacy/nix-store.cc
index e75e51445..f4b99d559 100644
--- a/lix/legacy/nix-store.cc
+++ b/lix/legacy/nix-store.cc
@@ -248,7 +248,7 @@ try {
         auto drv = TRY_AWAIT(store->derivationFromPath(storePath));
         StorePathSet outputs;
         if (forceRealise)
-            co_return store->queryDerivationOutputs(storePath);
+            co_return TRY_AWAIT(store->queryDerivationOutputs(storePath));
         for (auto & i : drv.outputsAndOptPaths(*store)) {
             if (!i.second.second)
                 throw UsageError("Cannot use output path of floating content-addressed derivation until we know what it is (e.g. by building it)");
diff --git a/lix/libstore/daemon.cc b/lix/libstore/daemon.cc
index c477166f1..8f5ccdfaf 100644
--- a/lix/libstore/daemon.cc
+++ b/lix/libstore/daemon.cc
@@ -358,7 +358,7 @@ static void performOp(AsyncIoRoot & aio, TunnelLogger * logger, ref<Store> store
             case WorkerProto::Op::QueryDerivationOutputs: {
                 // Only sent if server presents proto version <= 1.21
                 REMOVE_AFTER_DROPPING_PROTO_MINOR(21);
-                paths = store->queryDerivationOutputs(path);
+                paths = aio.blockOn(store->queryDerivationOutputs(path));
                 break;
             }
             default:
diff --git a/lix/libstore/remote-store.cc b/lix/libstore/remote-store.cc
index 57dfa11fa..5a53e6314 100644
--- a/lix/libstore/remote-store.cc
+++ b/lix/libstore/remote-store.cc
@@ -319,16 +319,18 @@ StorePathSet RemoteStore::queryValidDerivers(const StorePath & path)
 }
 
 
-StorePathSet RemoteStore::queryDerivationOutputs(const StorePath & path)
-{
+kj::Promise<Result<StorePathSet>> RemoteStore::queryDerivationOutputs(const StorePath & path)
+try {
     if (GET_PROTOCOL_MINOR(getProtocol()) >= 22) {
-        return Store::queryDerivationOutputs(path);
+        co_return TRY_AWAIT(Store::queryDerivationOutputs(path));
     }
     REMOVE_AFTER_DROPPING_PROTO_MINOR(21);
     auto conn(getConnection());
     conn->to << WorkerProto::Op::QueryDerivationOutputs << printStorePath(path);
     conn.processStderr();
-    return WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
+    co_return WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
+} catch (...) {
+    co_return result::current_exception();
 }
 
 
diff --git a/lix/libstore/remote-store.hh b/lix/libstore/remote-store.hh
index cec3c0044..5997790d2 100644
--- a/lix/libstore/remote-store.hh
+++ b/lix/libstore/remote-store.hh
@@ -62,7 +62,7 @@ public:
 
     StorePathSet queryValidDerivers(const StorePath & path) override;
 
-    StorePathSet queryDerivationOutputs(const StorePath & path) override;
+    kj::Promise<Result<StorePathSet>> queryDerivationOutputs(const StorePath & path) override;
 
     std::map<std::string, std::optional<StorePath>> queryPartialDerivationOutputMap(const StorePath & path, Store * evalStore = nullptr) override;
     std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override;
diff --git a/lix/libstore/store-api.cc b/lix/libstore/store-api.cc
index e51c95e1e..8701001d1 100644
--- a/lix/libstore/store-api.cc
+++ b/lix/libstore/store-api.cc
@@ -605,14 +605,16 @@ OutputPathMap Store::queryDerivationOutputMap(const StorePath & path, Store * ev
     return result;
 }
 
-StorePathSet Store::queryDerivationOutputs(const StorePath & path)
-{
+kj::Promise<Result<StorePathSet>> Store::queryDerivationOutputs(const StorePath & path)
+try {
     auto outputMap = this->queryDerivationOutputMap(path);
     StorePathSet outputPaths;
     for (auto & i: outputMap) {
         outputPaths.emplace(std::move(i.second));
     }
-    return outputPaths;
+    co_return outputPaths;
+} catch (...) {
+    co_return result::current_exception();
 }
 
 
diff --git a/lix/libstore/store-api.hh b/lix/libstore/store-api.hh
index 02db64ca0..af11187ec 100644
--- a/lix/libstore/store-api.hh
+++ b/lix/libstore/store-api.hh
@@ -444,7 +444,7 @@ public:
     /**
      * Query the outputs of the derivation denoted by `path`.
      */
-    virtual StorePathSet queryDerivationOutputs(const StorePath & path);
+    virtual kj::Promise<Result<StorePathSet>> queryDerivationOutputs(const StorePath & path);
 
     /**
      * Query the mapping outputName => outputPath for the given