[System] - Generic "Update Error" message is shown when attempting to "Check For Updates" with less than 250MB of free disk space.

[ZereoX]

Your system information

• Steam client version (build number or date): 1726683985 (Stable) / 1729917543 (Beta)
• Distribution (e.g. Ubuntu): SteamOS 3.6.19 / 3.7.0 (Deck) and Manjaro w/ Gnome 46 (Desktop)
• Opted into Steam client beta?: Issue is present on both Stable and Beta
• Have you checked for system updates?: Yes
• Steam Logs: steam-logs.tar.gz
• GPU: AMD Van Gogh RDNA 2.0 (Steam Deck) and RX 7800XT (Desktop)

Please describe your issue in as much detail as possible:

When attempting to Check For Updates or when changing the OS Update Channel if the user has less than 250MB of storage a generic Update Error will be shown. This issue does not prevent SteamOS from updating (Steam Deck), however even if the Steam client itself doesn't have an update the error message is shown.

Output from the Steam logs indicate the error that was triggered:

[2024-09-24 09:12:20] Background update loop checking for update. . .
[2024-09-24 09:12:20] Error: Steam needs 250MB of free disk space to update.
Checking for BIOS updates
BIOS version: F7A0131
Desired version: <none>
No updates configured for this bios

Update Error

Video

Update_Error.mp4

Steps for reproducing this issue:

1. Open the Devkit Management Tool (steam://install/943760).
2. Select the Steam Deck used for testing.
3. Select Remote Shell.
4. Run the following command: fallocate -l 500G temp <- Feel free to adjust the allocated size (in GB) based on your available device space.
5. Navigate to Steam > Settings > System.
6. Press Check For Updates.

Reproduction Rate: 5/5

Affected Platforms

• LCD: Yes
• OLED: Yes
• Desktop Deck-like session (gamescope -e -- steam -gamepadui -steamdeck): Yes
• Desktop: Yes, in Big Picture Mode

Actual result

• Generic error message is shown when attempting to update Steam / SteamOS with less than 250MB of disk space.

Expected result

• The error message should be specific and inform the user they must free up some space on their device to proceed with a Steam Client update. This would match the behaviour currently present at boot when the Steam client bootstrap tries to self-update.
• An error message for such a failure should only be shown if the Steam Client has a pending update.