Game backups are 0 bytes

[jveitchmichaelis]

Your system information

• Steam client version (build number or date): 1716584667 (Stable)
• Distribution (e.g. Ubuntu): Kubuntu 23.04
• Opted into Steam client beta?: No
• Have you checked for system updates?: Yes
• Steam Logs: Would prefer to not post publicly due to the amount of information in there.
• GPU: Nvidia RTX3090

Please describe your issue in as much detail as possible:

When trying to back up a game to disk, nothing is stored and the backup size is 0 bytes.

There are no log messages if Steam is run from a terminal. I've tried with disks formatted exfat, ext4, etc. all have sufficient storage space for the game (and either way there is no error message about the disk being full or incorrectly formatted).

Steps for reproducing this issue:

1. Attempt to back up an intstalled game to an external drive