X4: Foundations is getting cross-platform cloud saves - possible breakage coming for Linux

Egosoft have announced that X4: Foundations is finally getting cross-platform Steam Cloud saves, but desktop Linux users may need to make some backups.

Originally, the game had separate save paths for the Windows and Linux versions, but they're updating it so that players across Linux and Windows can actually share saves. This affects the Steam Deck too, which currently uses Proton by default to use the Windows version.

In the announcement the developer said you should make a backup of your save files, and once the update is live they suggest restarting Steam, loading X4 and then quitting to have it all moved around. For desktop Linux players, the saves should be in:

~/.config/EgoSoft/X4/

Some additional info they gave in the announcement:

Previously, the Steam Cloud had distinct storage locations for Windows files and for Linux files. This meant that saves did not automatically sync across the two platforms. (At the moment, the Steam Deck uses the Windows version of X4 by default, so it syncs with a Windows PC, but not with a Linux PC.)

With the changes, both Linux and Windows save files will be stored in the Steam Cloud with a Windows-like path. Upon syncing files from the Steam Cloud to a Linux machine, the paths will be translated to the corresponding Linux location on the disk, so that files are downloaded from and uploaded to the Windows location. Linux players will need to play the game at least once on Linux, so that Steam will upload any existing Linux files to the new cloud location.

These changes are an important step toward improving Linux and Steam Deck support for X4: Foundations (particularly, allowing us to use the native Linux version on the Steam Deck by default). They also enable a number of fixes and improvements that we’ve wanted to deliver for quite some time.

The change is planned to arrive Thursday, February 19, 2026.