# Exception after 2.4.0.0 Upgrade

**URL:** https://forum.duplicati.com/t/exception-after-2-4-0-0-upgrade/22704
**Category:** Support
**Created:** [September 15, 2026, 7:37pm UTC](https://forum.duplicati.com/t/exception-after-2-4-0-0-upgrade/22704 "2026-09-15T19:37:25Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![mewa](https://forum.duplicati.com/letter_avatar_proxy/v4/letter/m/3da27b/32.png) [@mewa](https://forum.duplicati.com/u/mewa)
#### Post date: [September 15, 2026, 7:37pm UTC](https://forum.duplicati.com/t/exception-after-2-4-0-0-upgrade/22704/1 "2026-09-15T19:37:25Z")

</div>

I recently upgraded my long-standing install to 2.4.0.0, using the windows service option. I did all the re-configuration required (pointing to the old database folder, adding the database encryption key). Now I am running into a new problem:

For one of my backups, the source data was on a mapped network drive. Now that duplicati is running as a service, this mapping is no longer active. So I am trying to edit the “Source Data” to use the UNC path. The problem is, that whether I add the UNC Path (say, \\10.0.0.5\Data) as a “Manually type path” under the “File System” source, or as a “Windows Share SMB”, the following happens:

1. I am able to add the path and the “Test Now” is successful
2. In the SMB screen, I am able to hit the “Browse” button and see the folder structure
3. BUT after I hit “Use remote source” to return to the main screen, and when try to expand the remote source itself (to select individual subfolders), I get “An error occurred” `Unhandled exception in webserver request to /api/v1/filesystem...` with the following detail:

```plaintext
# Exception

    System.Exception: Failed to process the path: Could not find a part of the path '\\?\X:\dupl-smb-efhcln6h'.

     ---> System.IO.DirectoryNotFoundException: Could not find a part of the path '\\?\X:\dupl-smb-efhcln6h'.

       at System.IO.Enumeration.FileSystemEnumerator`1.Init()

       at System.IO.Enumeration.FileSystemEnumerable`1..ctor(String directory, FindTransform transform, EnumerationOptions options, Boolean isNormalized)

       at System.IO.Enumeration.FileSystemEnumerableFactory.UserEntries(String directory, String expression, EnumerationOptions options)

       at System.IO.Directory.InternalEnumeratePaths(String path, String searchPattern, SearchTarget searchTarget, EnumerationOptions enumerationOptions)

       at Duplicati.Library.Common.IO.SystemIOWindows.EnumerateFileSystemEntries(String path)

       at Duplicati.WebserverCore.Endpoints.V1.Filesystem.ListFolderAsNodes(String entrypath, Boolean skipFiles, Boolean showHidden)+MoveNext()

       at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)

       at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)

       at Duplicati.WebserverCore.Endpoints.V1.Filesystem.Execute(String path, Boolean onlyFolders, Boolean showHidden)

       --- End of inner exception stack trace ---

       at Duplicati.WebserverCore.Endpoints.V1.Filesystem.Execute(String path, Boolean onlyFolders, Boolean showHidden)

       at lambda_method255(Closure, EndpointFilterInvocationContext)

       at Duplicati.WebserverCore.Middlewares.HostnameFilter.InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next)

       at Duplicati.WebserverCore.Middlewares.LanguageFilter.InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next)

       at Microsoft.AspNetCore.Http.RequestDelegateFactory.<ExecuteValueTaskOfObject>g__ExecuteAwaited|130_0(ValueTask`1 valueTask, HttpContext httpContext, JsonTypeInfo`1 jsonTypeInfo)

       at Microsoft.AspNetCore.Http.RequestDelegateFactory.<>c __DisplayClass102_2.<<HandleRequestBodyAndCompileRequestDelegateForJson>b__ 2>d.MoveNext()

    --- End of stack trace from previous location ---

       at Duplicati.WebserverCore.Middlewares.WebsocketExtensions.<>c __DisplayClass0_0.<<UseNotifications>b__ 0>d.MoveNext()

    --- End of stack trace from previous location ---

       at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddlewareImpl.<Invoke>g__Awaited|10_0(ExceptionHandlerMiddlewareImpl middleware, HttpContext context, Task task)

# Message

    Unhandled exception in webserver request to /api/v1/filesystem

```

I also have a second error logged, `Cannot find any MS SQL Server instance. MS SQL Server is probably not installed....` but I believe that that is not related.

Therefore, I am not able to resume the previous backup. Any suggestions are much appreciated, and I am happy to provide more detail! Thanks!

---

<div class="post-metadata">

### Author: ![mewa](https://forum.duplicati.com/letter_avatar_proxy/v4/letter/m/3da27b/32.png) [@mewa](https://forum.duplicati.com/u/mewa)
#### Post date: [September 18, 2026, 1:07pm UTC](https://forum.duplicati.com/t/exception-after-2-4-0-0-upgrade/22704/2 "2026-09-18T13:07:28Z")

</div>

Follow up - the backup job currently fails in the original configuration, as it cannot find the mapped network drive/source files. While the “[Dynamic mapped pre/post script drive](https://forum.duplicati.com/t/cannot-access-network-folder/1436/7)” (from @[JonMikelV](https://forum.duplicati.com/u/jonmikelv)) is a successful workaround, I think there may still be issues leading to the exception above, where the SMB/UNC path mapping may be broken.

---

<div class="post-metadata">

### Author: ![mewa](https://forum.duplicati.com/letter_avatar_proxy/v4/letter/m/3da27b/32.png) [@mewa](https://forum.duplicati.com/u/mewa)
#### Post date: [October 7, 2026, 6:55pm UTC](https://forum.duplicati.com/t/exception-after-2-4-0-0-upgrade/22704/3 "2026-10-07T18:55:25Z")

</div>

This persists in 2.4.0.1\_stable\_2026-10-07. Any help is much appreciated!