Unable to sync files down to mobile device

[hax0rbana-adam]

⚠️ Before posting ⚠️

• This is a bug, not a question or an enhancement.
• I've searched for similar issues and didn't find a duplicate.
• I've written a clear and descriptive title for this issue, not just "Bug" or "Crash".
• I agree to follow Nextcloud's Code of Conduct.

Steps to reproduce

The core issue is that while Nextcloud's UI shows files getting downloaded, and the web server agrees, but the content is not being written to the phone's storage.

A few weeks ago, I ran into a similar issue where syncing a folder didn't sync any contents of the folder (#15102 and possibly related: #15545). The icon saying it was synced was there and persistent, but the folders and files were not. At the time, I was able to download the files in the folder and it created the directory structure on disk.

This issue is separate from those above. Now I can't sync any files, nor downgrade to a version of Nextcloud that can do so.

This does not seem to affect files which were already downloaded before this bug was introduced. The files are still visible in the Files app and can be used by other apps.

This has been reproduced on multiple phones, both with the latest version of Nextcloud from F-Droid, both connecting to the same server.

Steps to reproduce

1. Go to your list of folders in the Nextcloud app
2. Click the vertical ellipsis on a folder which contains at least one file
3. Click Sync
4. Observe that the UI shows a syncing icon and then a green check mark
5. Navigate into the folder, observe that none of the files were downloaded to the device
6. Return to the previous screen, observe that the green check icon is now gone
7. In the Files app, navigate to the folder location (Android/media/com.nextcloud.client/...
8. Observe that neither the folder nor its files are present
9. Repeat with a file and observe that also doesn't get put into the phone's storage. Clicking while the icon claims that is is synced, doesn't open the file, it doesn't appear in the Apps folder, and if you navigate away and come back Nextcloud shows it's not downloaded. There's a notification dialog that says "Error occurred while downloading files". There is no additional details when trying to expand it.

Relevant settings

When I go to the Android Settings app -> Apps -> Special app access -> All files access, Nextcloud is listed and it says "Allowed".

In the Nextcloud settings, the data storage location show I'm saving data to internal storage and using 35.4 GB / 109.7 GB. Allow access from other apps is enabled.

Expected behaviour

Syncing files causes them to be available on the phone in the Files app.

Actual behaviour

Files seem to download (per the server logs), but never get written to storage.

Android version

16

Device brand and model

Pixel 8a

Stock or custom OS?

Custom (explain in "additional information")

Nextcloud android app version

33.1.2

Nextcloud server version

Hub 25 (aka 32.0.11)

Using a reverse proxy?

No

Android logs

No response

Server error logs

No errors on the server side.

The server logs show requests for the folder **and each of the files** in the folder. There are no errors showing on the web server. It serves up the content with a 200 status code.

In the nextcloud server logs (data/nextcloud.log), there's a warning "The requested alias \"OCP\\IServerContainer\" is deprecated. Please request \"Psr\\Container\\ContainerInterface\" directly. This alias will be removed in a future Nextcloud version." but no errors.

So it appears the folders are getting downloaded by the app, but the app just isn't putting them onto the phone's storage.

Additional information

I'm not using a beta version of the app and don't have USB connections enabled. I'll try to find a test device and gets logs from that to post in this ticket.

GrapheneOS. Not using storage scopes.

Unfortunately I can not downgrade to a previous version of the Nextcloud app to test for comparison. As such, I can't point to a specific version where this problem got worse.

[hax0rbana-adam]

All files in my testing were ASCII filenames consisting of numbers, letters, spaces, dashes and an underscore. No unicode characters or special characters such as a colon.

[qudiqudi]

Same here on 33.1.2: the app shows the file downloading and the server returns 200 with the full file, but nothing is written to the device and you get "Error occurred while downloading files". Same when opening a file from a third-party app (a KeePass .kdbx, in my case). One environment difference that may help triage — I'm behind a reverse proxy and you're not — so this doesn't look proxy-related.

Reverse-proxy access log, same file, before and after downgrading the client (domain/user/path redacted):

# Nextcloud-android/33.1.2 — server returns 200 with the full file, but app shows "Error occurred while downloading files"
GET /remote.php/dav/files/<user>/.../<file>.pdf   200   1,225,817 bytes   Nextcloud-android/33.1.2

# Nextcloud-android/33.1.0 — same file, 200, and it actually downloads to the device
GET /remote.php/dav/files/<user>/.../<file>.pdf   200   1,242,015 bytes   Nextcloud-android/33.1.0

(Both are the full ~1.2 MB file; the small size difference is just a newer file version. Server never errors — it serves 200 in both cases. The only thing that changed is the client version.)

This appears to be a regression of #17055 (fixed by #17058, which shipped in 33.1.1). 33.1.1 stable worked fine for me; 33.1.2 brought the failure back.

On the downgrade you couldn't find: 33.1.0 works — it predates the original bug. F-Droid serves it as a plain APK: https://f-droid.org/repo/com.nextcloud.client_330010090.apk (uninstall first; the signature differs from the Play build). After downgrading, downloads worked again. 33.1.1 stable should also be fine, since it carried the #17058 fix.

Environment: Nextcloud server 33.0.3, Android client 33.1.2 → downgraded to 33.1.0.

[bjinthahouse]

I'm facing the same issue. Downloading files on an Android Client (two different devices) results in "100% - An error occurred while downloading files".
My nextcloud instance is on latest stable version 33.0.5. I'm also behind a Reverse Proxy (haproxy).
Interestingly the app suggest a successful download, because I see a green check mark besides the file. But the notification says "An error occurred while downloading files". When I reload the file list, the check mark vanishes.

[djagar]

The same here, but with Android App v33.1.1. The files are not downloaded to the device, an error is shown in the notification panel.
Completely reinstalling doesn't help either.
Pixel 6 with latest Android 16, all updates installed.

[GuSchmi]

With Android App v33.1.0 the download (of pdf files) works fine, v33.1.2 fails.

[alperozturk96]

duplication of #17079

[hax0rbana-adam]

This issue applies to small files and happens over a gigabit LAN connection, which doesn't match what was described in #17079. It's possible that a code change could fix both of these at once though.

[BobSilent]

facing exact same issue, since some days, my files are also small, just some kb.

[alperozturk96]

@hax0rbana-adam Please share your feedback with QA APK you need to login to download it.

If the issue still persists for you we can re-open this issue and create another PR.

Thank you.