uSync export error - "The requestId field is required"

[eqtr-ab (bruag)]

Umbraco version: 16.2.0

uSync version: 16.0.8

I’m trying to export everything from a test site to a uSync ZIP file, but doing so gives a “The requestId field is required” error.

In the POST API call to the Perform endpoint to start the export process, I can see a request ID field which is blank:

{"requestId":"","action":"Export","options":{"group":"all","force":false,"clean":false,"files":true,"clientId":"","set":"Default"},"stepNumber":0}

The same request ID field is also blank for other calls to Perform, such as running a Settings report, but the error does not occur there:

{"requestId":"","action":"Report","options":{"group":"settings","force":false,"clean":false,"files":false,"clientId":"","set":"Default"},"stepNumber":0}

Can anybody help me resolve this please?

[eqtr-ab (bruag)]

I now believe the request ID message is a red herring, on reviewing the logs I’ve found an “Access denied” error occurring during the Export process - the stack trace suggests that this is occurring due to an attempt to delete a file.

System.UnauthorizedAccessException: Access to the path 'E:\(path truncated)\uSync\v16\Languages\en-us.config' is denied.
   at System.IO.FileSystem.DeleteFile(String fullPath)
   at System.IO.File.Delete(String path)
   at uSync.BackOffice.Services.SyncFileService.DeleteFile(String path)
   at uSync.BackOffice.Services.SyncFileService.OpenWrite(String path)
   at uSync.BackOffice.Services.SyncFileService.SaveXElementAsync(XElement node, String filename)

I’m going to try and resolve this with server configuration.