Zoom Linux 7.0.5 on Kubuntu 24.04: chat file downloads always fail, but preview and web download work

Hello,

I am experiencing a reproducible issue with the Zoom desktop client on Linux.

Environment:

• OS: Kubuntu 24.04

• Desktop: KDE Plasma

• Session type: X11

• Zoom client: 7.0.5 (3034)

• Package type: official .deb, not Snap

• Install path: /opt/zoom

• GPU: Intel integrated graphics + NVIDIA GeForce RTX 4050 Laptop GPU

• xdg-desktop-portal: installed, KDE and GTK portals detected

Problem:

When I try to download files from Zoom chat in the desktop client, the download always fails. Zoom opens the file save dialog, I choose a destination such as ~/Downloads, /tmp, or another folder, but Zoom immediately shows Failed.

The same files can be downloaded successfully from the Zoom web version. File previews inside the desktop client also work, so the file is accessible and the network side seems to be fine. The problem appears to be specific to saving/downloading files from the Linux desktop client.

What I tested:

1. Verified write permissions:

touch ~/Downloads/test.txt && rm ~/Downloads/test.txt && echo "Downloads OK"

Result:

Downloads OK

So the target directory is writable.

2. Tried saving to different locations:

• ~/Downloads

• /tmp

• other folders

Result: always Failed.

3. Tried with and without GTK/KDE portal behavior:

GTK_USE_PORTAL=0 zoom
QT_QPA_PLATFORMTHEME=gtk3 zoom

Result: still Failed.

4. Reset Zoom profile completely:

pkill zoom
mv ~/.zoom ~/.zoom.broken
mv ~/.config/zoomus.conf ~/.config/zoomus.conf.broken

After launching Zoom again, it started with a clean profile and printed:

Can't load/home/reallyfire/.config/zoomus.conf
Linux Client Version is 7.0.5 (3034)
XDG_CURRENT_DESKTOP = KDE; DESKTOP_SESSION = plasma; XDG_SESSION_TYPE = x11
Zoom package arch is 64bit, runing OS arch is x86_64, snap package 0

Result: the download problem still happens on the clean profile.

5. Before resetting the profile, Zoom logs repeatedly showed SQLCipher errors:

ERROR CORE sqlcipher_page_cipher: hmac check failed for pgno=1
ERROR CORE sqlite3Codec: error decrypting page 1 data: 1
ERROR CORE sqlcipher_codec_ctx_set_error 1

After resetting the profile, these SQLCipher errors disappeared, but the file download issue remained. So the corrupted local database was not the root cause of the download failure.

6. I ran strace while reproducing the issue:

strace -f -e trace=openat,creat,rename -s 300 -o /tmp/zoom-download.strace zoom

After selecting ~/Downloads in the save dialog, the trace shows Zoom opening the directory:

openat(AT_FDCWD, "/home/reallyfire/Downloads", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = ...

But there is no corresponding call like:

openat(... "/home/reallyfire/Downloads/<filename>", O_CREAT ...)

This suggests that Zoom never actually attempts to create the destination file. The failure seems to happen before the file write starts.

7. The Zoom terminal log also shows repeated messages like:

Error: Send error, 22 Invalid argument

but no clear file download error.

Expected behavior:

When I choose a destination in the save dialog, Zoom should download and save the file.

Actual behavior:

Zoom immediately reports Failed. No file is created in the target directory.

Important detail:

The same files downloads successfully from the Zoom web client, and file preview works in the desktop client. Only saving/downloading from the Linux desktop client fails.

Could this be a regression in Zoom Linux 7.0.5, possibly related to the chat file download flow or the KDE/X11 file dialog integration?

Please let me know if there are additional debug logs I can provide.