kopia
Snapshot Mounting in KopiaUI Fails While Command Line Succeeds - Windows 10
Description:
There is an issue with KopiaUI where mounting a snapshot to the Z:\ drive fails with the error Z:\ is unavailable. However, when running the same command directly via the command line, the snapshot mounts successfully to Z:\. This suggests that KopiaUI may be using arguments or methods that cause inconsistent behavior when handling certain drive letters.
Steps to Reproduce:
- Open KopiaUI on Windows 10.
- Try to mount a snapshot to
Z:\using the UI's mount feature. - Observe the error:
Z:\ is unavailable. If the location is on this PC, make sure the device or drive is connected.... - Run the same command via Command Prompt:
C:\Users\Username\Downloads\KopiaUI-0.17.0-win\resources\server\kopia.exe mount <snapshot ID> Z: --browse - Observe that the snapshot mounts successfully via the command line.
Expected Behavior:
KopiaUI should behave consistently with the command line, allowing the snapshot to be mounted to the Z:\ drive without errors.
Actual Behavior:
KopiaUI fails to mount the snapshot to Z:\, while the command line mounts it without issue.
Environment:
- KopiaUI Version: 0.17.0
- OS: Windows 10
-
Snapshot Command (via CLI):
C:\Users\Username\Downloads\KopiaUI-0.17.0-win\resources\server\kopia.exe mount <snapshot ID> Z: --browse - Snapshot ID: k9857cfff2abadaf5f0eb2a26780dae1f
- Source Path: C:\Users\Username\Music
- Snapshot Size: 16.8 GB
Troubleshooting Attempts:
- Successfully mounted the snapshot to
Z:\via the command line using the same parameters. - The issue is isolated to the UI, as the CLI mount works without any issues, suggesting that KopiaUI might be passing additional or incorrect arguments leading to inconsistent behavior.
Possible Causes:
- UI Argument Handling: KopiaUI may be handling arguments incorrectly when attempting to mount snapshots, leading to drive letter conflicts or misconfiguration.
-
Inconsistent UI Behavior: KopiaUI might be executing additional logic or using different system calls than the command line version of
kopia.exe, which could be causing the issue.
Suggested Fix:
- Investigate the argument handling logic in KopiaUI when performing snapshot mounting.
- Ensure that the UI is using the same methods and arguments as the command line interface to prevent inconsistent behavior.
- Provide more detailed error logging in the UI to help diagnose potential discrepancies between UI and CLI behavior.
References:
- Kopia documentation on mounting snapshots
- Related issue on GitHub discussing mounting inconsistencies
Same issue here. I could mount a snapshot using CLI but not GUI: I have the same "location unavailable" error. Interestingly, I could only mount the snapshot correctly using powershell. When I tried with CMD, I had the same "location unavailable" error. Perhaps that is related to the GUI behaviour ?
Good evening Ladies and Gents. I can reproduce the behaviour in Windows 10 using GUI. CMD yields success. Mounting via GUI works in Windows 11.
Probably has to do with some windows user privileges/permissions subtleties.
When i start kopia mount all Z: from a regular command prompt, all mounts as it should and Explorer auto-opens disk Z: folder right there.
BUT when i start kopia mount all Z: from an elevated (Run as administrator) command prompt, I see Mounted 'kf859d79.................34758' on Z: but NO disk Z: is actually available/visible from Explorer.
In order to mount a Kopia repository as a filesystem on Windows, Kopia uses WebDAV, which depends on the WebClient service being installed and running. However, WebClient (WebDAV Redirector) is considered legacy, and Microsoft has been phasing it out, especially on Windows Server editions. If the service is only running under a different (admin) account (or missing entirely in future Windows versions), it makes kopia mount non-functional on Windows.
Would it be possible to implement native mounting on Windows or offer an alternative to WebDAV?
Greetings! Thank you very much for the marvel you do!
Apparently, someone I know has the same issue on the up-to-date Windows 11, and only on KopiaUI, where a manual CLI command - succeeds.
KopiaUI
When the require snapshot is selected, and button "Mount as Local Filesystem" pressed, the following appears in Network tab of DevTools of KopiaUI.
It's worth to mention that the same happens with and without KopiaUI launched with administrative permissions.
Response
Status: HTTP 404.
{
"code": "NOT_FOUND",
"error": "mount point not found"
}
Request
fetch("https://127.0.0.1:6219/api/v1/mounts/kd2bda348ee21fd60302d4f3ae37932c7", {
"headers": {
"accept": "application/json, text/plain, */*",
"accept-language": "lt",
"authorization": "Basic [redacted]",
"priority": "u=1, i",
"sec-ch-ua": "\"Not.A/Brand\";v=\"99\", \"Chromium\";v=\"136\"",
"sec-ch-ua-mobile": "?0",
"sec-ch-ua-platform": "\"Windows\"",
"sec-fetch-dest": "empty",
"sec-fetch-mode": "cors",
"sec-fetch-site": "same-origin",
"x-kopia-csrf-token": "[redacted]"
},
"referrer": "https://127.0.0.1:6219/snapshots/dir/kd2bda348ee21fd60302d4f3ae37932c7",
"referrerPolicy": "strict-origin-when-cross-origin",
"body": null,
"method": "GET",
"mode": "cors",
"credentials": "include"
});
Stacktrace
(anonymous) @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:51
xhr @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:51
aS @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:53
_request @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:54
request @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:53
Nr.<computed> @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:54
(anonymous) @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:49
fetchDirectory @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:661
componentDidMount @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:661
E1 @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:48
Di @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:48
E1 @ https://127.0.0.1:6219/assets/index-B7f9HFI_.js:48
...
Kopia CLI
List all snapshots
% kopia.exe --config-file "C:\Users\user\AppData\Roaming\kopia\repository.config" snapshot list
Enter password to open repository:
user@laptop:D:\
2025-07-07 22:50:08 EET k73e5cb83f1879931f9e6a4184bb6d0bf 350 GB drwxrwxrwx files:78155 dirs:10191 (latest-3..4)
+ 1 identical snapshots until 2025-07-07 23:16:23 EET
2025-07-07 23:17:02 EET k200b652040882239f4eb7ac6201e9504 349.5 GB drwxrwxrwx files:78142 dirs:10186 (latest-2,daily-2)
2025-07-11 16:40:08 EET kd2bda348ee21fd60302d4f3ae37932c7 349.6 GB drwxrwxrwx files:78159 dirs:10190 (latest-1,hourly-1,daily-1,weekly-1,monthly-1,annual-1)
Attempt to mount all snapshots
% kopia.exe --config-file "C:\Users\saule\AppData\Roaming\kopia\repository.config" mount
Enter password to open repository:
Mounted 'all' on Z:
HINT: Pass --browse to automatically open file browser.
Press Ctrl-C to unmount.
Attempt to mount the latest snapshot
% kopia.exe --config-file "C:\Users\saule\AppData\Roaming\kopia\repository.config" mount kd2bda348ee21fd60302d4f3ae37932c7 Z:
Enter password to open repository:
Mounted 'kd2bda348ee21fd60302d4f3ae37932c7' on Z:
Press Ctrl-C to unmount.
The above are the details available, and I will attempt to gather more if required.
I haven't dug deeper, yet. Meanwhile, what might it be? Thanks, in advance!
Please stay safe and astronomical!
