Updated
---------- Post added at 07:40 PM ---------- Previous post was at 07:06 PM ----------
Solved
Renaming ClientRegistry.blob
It's possible you may be receiving this message if Steam isn't properly configured or if configuration files are missing.
Renaming the ClientRegistry.blob will cause Steam to re-download fresh copies of required configuration files, which can solve a large number of issues.
On Windows
If the issue is isolated to a few Steam games, please exit from Steam and go to the Steamapps folder (default is C
Program Files\Steam\Steamapps) and delete any listed .ncf files for the specific games. Once complete, please restart Steam to test the issue.
On Mac
If the issue is isolated to a few Steam games, please exit from Steam and go to the ~/Users/[username]/Library/Application Support/Steam/SteamApps and delete any listed .ncf files for the specific games. Once complete, please restart Steam to test the issue.
---------- Post added at 07:43 PM ---------- Previous post was at 07:40 PM ----------
https://support.steampowered.com/kb_article.php?ref=5483-YUFN-0521