Failed to update mod list: could not create a temporary file

[giantdwarf17]

After following the instructions I began downloading mods from Nexus. At first everything was fine, but as soon as I tried enabling the first mod I started getting an error message saying "failed to update mod list: Failed to save '{}', could not create a temporary file: {} (error {})"

Here are screenshots of the logs, although they are hard to read for some reason:

I found a similar issue on reddit and used their advice to create a temp folder within the proton prefix, but that didn't seem to do anything either.

[giantdwarf17]

Nevermind, after looking at the logs I realized I had created the temp folder in the wrong location lol. I had originally created the folder ~/.steam/root/steamapps/compatdata/22380/pfx/drive_c/users/steamuser/AppData/Local/Temp, as the reddit post suggested. But after reading the logs I realized it was looking for a temp folder in ~/.steam/root/steamapps/compatdata/22380/pfx/drive_c/users/steamuser/Temp. After creating that folder the error went away.

[giantdwarf17]

Reopening because if this is a common issue then the installer script could probably create the folder automatically.

[Ryder17z]

i just encountered this issue as well.

[hvl-mighty44]

Had same issue. Issue due to MO2 removing tmp folder. I sovlved my issue by adding Temp folder to ~/.steam/root/steamapps/compatdata/22xxx(LOOK for C drive with JAVA file folder in it)/pfx/drive_c/users/steamuser/Temp. And add\make a file to the folder and set chattr +i to that file to prevent Temp folder to be deleted.

[MrAwesome]

Just encountered this as well, didn't do anything special with my setup and hit this while trying to install.

[nalabrie]

Also just encountered this on Fedora 41 (Bazzite, KDE, nvidia) with a fresh install of Skyrim SE and a fresh install of MO2. Making the Temp folder in the manner @hvl-mighty44 suggested worked for me.

EDIT: So it worked one time and now is no longer working so there must be more to this issue. Perhaps involving selecting "portable instance" during setup? I started from scratch and just let it default to "global instance" and have no issues out of the box. And to my understanding, this isn't really a global instance since it is contained to the Skyrim SE prefix. I don't believe any official instructions provided warn against using the portal optiol during MO2 setup, so if that is indeed the issue then maybe it is worth pointing out during the install section.

EDIT 2: Ok now I am really confused. With the "global instance" the only thing I added was SKSE to test launching the game and that worked. I closed Skyrim, closed MO2, downloaded some mods manually, and when launching MO2 again it popped up a message saying that the instance was not there and a new one needed created and upon creating it the original error kept happening again. So weird, I give up for the time being.