This error usually has nothing to do with your actual hard drive space. Instead, it is almost always caused by modern Windows security features, broken Games for Windows Live (GFWL) files, or folder read/write permissions.
Before diving into complex troubleshooting, try giving the game higher system privileges. Windows often blocks GTA 4 from writing new save files to your Documents folder. gta 4 save failed please check your storage link
If you are playing the updated on Steam, Games for Windows Live has already been removed by Rockstar. If you still get this error on the Complete Edition: This error usually has nothing to do with