diff --git a/backend/FwHeadless/Program.cs b/backend/FwHeadless/Program.cs
index 261047d99..3d3484df2 100644
--- a/backend/FwHeadless/Program.cs
+++ b/backend/FwHeadless/Program.cs
@@ -86,7 +86,8 @@
     logger.LogDebug("crdtFile: {crdtFile}", crdtFile);
     logger.LogDebug("fwDataFile: {fwDataFile}", fwDataProject.FilePath);
 
-    var fwdataApi = SetupFwData(fwDataProject, srService, projectCode, logger, fwDataFactory);
+    var fwdataApi = await SetupFwData(fwDataProject, srService, projectCode, logger, fwDataFactory);
+    using var deferCloseFwData = fwDataFactory.DeferClose(fwDataProject);
     var crdtProject = await SetupCrdtProject(crdtFile, projectLookupService, projectId, projectsService, projectFolder, fwdataApi.ProjectId, config.Value.LexboxUrl);
 
     var miniLcmApi = await services.OpenCrdtProject(crdtProject);
@@ -96,15 +97,14 @@
 
     var result = await syncService.Sync(miniLcmApi, fwdataApi, dryRun);
     logger.LogInformation("Sync result, CrdtChanges: {CrdtChanges}, FwdataChanges: {FwdataChanges}", result.CrdtChanges, result.FwdataChanges);
-    fwDataFactory.CloseProject(fwDataProject);
 
     await crdtSyncService.Sync();
-    var srResult2 = srService.SendReceive(fwDataProject, projectCode);
+    var srResult2 = await srService.SendReceive(fwDataProject, projectCode);
     logger.LogInformation("Send/Receive result after CRDT sync: {srResult2}", srResult2.Output);
     return TypedResults.Ok(result);
 }
 
-static FwDataMiniLcmApi SetupFwData(FwDataProject fwDataProject,
+static async Task<FwDataMiniLcmApi> SetupFwData(FwDataProject fwDataProject,
     SendReceiveService srService,
     string projectCode,
     ILogger<Program> logger,
@@ -112,12 +112,12 @@ static FwDataMiniLcmApi SetupFwData(FwDataProject fwDataProject,
 {
     if (File.Exists(fwDataProject.FilePath))
     {
-        var srResult = srService.SendReceive(fwDataProject, projectCode);
+        var srResult = await srService.SendReceive(fwDataProject, projectCode);
         logger.LogInformation("Send/Receive result: {srResult}", srResult.Output);
     }
     else
     {
-        var srResult = srService.Clone(fwDataProject, projectCode);
+        var srResult = await srService.Clone(fwDataProject, projectCode);
         logger.LogInformation("Send/Receive result: {srResult}", srResult.Output);
     }
 
diff --git a/backend/FwHeadless/SendReceiveHelpers.cs b/backend/FwHeadless/SendReceiveHelpers.cs
index 9c8ac9494..078011bd8 100644
--- a/backend/FwHeadless/SendReceiveHelpers.cs
+++ b/backend/FwHeadless/SendReceiveHelpers.cs
@@ -17,10 +17,14 @@ public SendReceiveAuth(FwHeadlessConfig config) : this(config.LexboxUsername, co
 
     public record LfMergeBridgeResult(string Output, string ProgressMessages);
 
-    private static LfMergeBridgeResult CallLfMergeBridge(string method, IDictionary<string, string> flexBridgeOptions)
+    private static async Task<LfMergeBridgeResult> CallLfMergeBridge(string method, IDictionary<string, string> flexBridgeOptions)
     {
         var progress = new StringBuilderProgress();
-        LfMergeBridge.LfMergeBridge.Execute(method, progress, flexBridgeOptions.ToDictionary(), out var lfMergeBridgeOutputForClient);
+        var lfMergeBridgeOutputForClient = await Task.Run(() =>
+        {
+            LfMergeBridge.LfMergeBridge.Execute(method, progress, flexBridgeOptions.ToDictionary(), out var output);
+            return output;
+        });
         return new LfMergeBridgeResult(lfMergeBridgeOutputForClient, progress.ToString());
     }
 
@@ -45,7 +49,7 @@ private static Uri BuildSendReceiveUrl(string baseUrl, string projectCode, SendR
         return builder.Uri;
     }
 
-    public static LfMergeBridgeResult SendReceive(FwDataProject project, string? projectCode = null, string baseUrl = "http://localhost", SendReceiveAuth? auth = null, string fdoDataModelVersion = "7000072", string? commitMessage = null)
+    public static async Task<LfMergeBridgeResult> SendReceive(FwDataProject project, string? projectCode = null, string baseUrl = "http://localhost", SendReceiveAuth? auth = null, string fdoDataModelVersion = "7000072", string? commitMessage = null)
     {
         projectCode ??= project.Name;
         var fwdataInfo = new FileInfo(project.FilePath);
@@ -65,10 +69,10 @@ public static LfMergeBridgeResult SendReceive(FwDataProject project, string? pro
             { "user", "LexBox" },
         };
         if (commitMessage is not null) flexBridgeOptions["commitMessage"] = commitMessage;
-        return CallLfMergeBridge("Language_Forge_Send_Receive", flexBridgeOptions);
+        return await CallLfMergeBridge("Language_Forge_Send_Receive", flexBridgeOptions);
     }
 
-    public static LfMergeBridgeResult CloneProject(FwDataProject project, string? projectCode = null, string baseUrl = "http://localhost", SendReceiveAuth? auth = null, string fdoDataModelVersion = "7000072")
+    public static async Task<LfMergeBridgeResult> CloneProject(FwDataProject project, string? projectCode = null, string baseUrl = "http://localhost", SendReceiveAuth? auth = null, string fdoDataModelVersion = "7000072")
     {
         projectCode ??= project.Name;
         var fwdataInfo = new FileInfo(project.FilePath);
@@ -84,6 +88,6 @@ public static LfMergeBridgeResult CloneProject(FwDataProject project, string? pr
             { "languageDepotRepoUri", repoUrl.ToString() },
             { "deleteRepoIfNoSuchBranch", "false" },
         };
-        return CallLfMergeBridge("Language_Forge_Clone", flexBridgeOptions);
+        return await CallLfMergeBridge("Language_Forge_Clone", flexBridgeOptions);
     }
 }
diff --git a/backend/FwHeadless/SendReceiveService.cs b/backend/FwHeadless/SendReceiveService.cs
index 37023dc8f..d924034f6 100644
--- a/backend/FwHeadless/SendReceiveService.cs
+++ b/backend/FwHeadless/SendReceiveService.cs
@@ -5,9 +5,9 @@ namespace FwHeadless;
 
 public class SendReceiveService(IOptions<FwHeadlessConfig> config)
 {
-    public SendReceiveHelpers.LfMergeBridgeResult SendReceive(FwDataProject project, string? projectCode, string? commitMessage = null)
+    public async Task<SendReceiveHelpers.LfMergeBridgeResult> SendReceive(FwDataProject project, string? projectCode, string? commitMessage = null)
     {
-        return SendReceiveHelpers.SendReceive(
+        return await SendReceiveHelpers.SendReceive(
             project: project,
             projectCode: projectCode,
             baseUrl: config.Value.HgWebUrl,
@@ -17,9 +17,9 @@ public SendReceiveHelpers.LfMergeBridgeResult SendReceive(FwDataProject project,
         );
     }
 
-    public SendReceiveHelpers.LfMergeBridgeResult Clone(FwDataProject project, string? projectCode)
+    public async Task<SendReceiveHelpers.LfMergeBridgeResult> Clone(FwDataProject project, string? projectCode)
     {
-        return SendReceiveHelpers.CloneProject(
+        return await SendReceiveHelpers.CloneProject(
             project: project,
             projectCode: projectCode,
             baseUrl: config.Value.HgWebUrl,
diff --git a/backend/FwLite/FwDataMiniLcmBridge/FwDataFactory.cs b/backend/FwLite/FwDataMiniLcmBridge/FwDataFactory.cs
index fb085fefe..78fc74092 100644
--- a/backend/FwLite/FwDataMiniLcmBridge/FwDataFactory.cs
+++ b/backend/FwLite/FwDataMiniLcmBridge/FwDataFactory.cs
@@ -1,5 +1,6 @@
 using FwDataMiniLcmBridge.Api;
 using FwDataMiniLcmBridge.LcmUtils;
+using LexCore.Utils;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
@@ -130,4 +131,9 @@ public void CloseProject(FwDataProject project)
         if (lcmCache is null) return;
         cache.Remove(cacheKey);
     }
+
+    public IDisposable DeferClose(FwDataProject project)
+    {
+        return Defer.Action(() => CloseProject(project));
+    }
 }
diff --git a/backend/FwLite/FwDataMiniLcmBridge/FwDataMiniLcmBridge.csproj b/backend/FwLite/FwDataMiniLcmBridge/FwDataMiniLcmBridge.csproj
index 457f4d84e..2192d7724 100644
--- a/backend/FwLite/FwDataMiniLcmBridge/FwDataMiniLcmBridge.csproj
+++ b/backend/FwLite/FwDataMiniLcmBridge/FwDataMiniLcmBridge.csproj
@@ -28,6 +28,7 @@
         <InternalsVisibleTo Include="LcmDebugger" />
     </ItemGroup>
     <ItemGroup>
+        <ProjectReference Include="..\..\LexCore\LexCore.csproj" />
         <ProjectReference Include="..\MiniLcm\MiniLcm.csproj" />
     </ItemGroup>