Steam - Unable to sync with Cloud

When I try to open MPQ on Steam I get this:

"Steam was unable to sync your files for MPQ with the Steam Cloud

If you have launched this application from another computer, your application settings and/or progress may not be in sync with what is stored in the Cloud. If you launch the application now, you may lose those changes or progress."

The only other place it's installed is on my Android, and I've opened and closed the app there.

Edit - Might just be an issue with Steam. Anyone else having this problem?