I have an assembly that has some errors in the mates (Concentric mate with 'invalid face'). However, SolidWorks doesn't prompt any message or error. If you look at the assembly you wouldn't be able to tell that some of the mates have errors, unless you actually open the mates and you'll see the 'face invalid' message'. I tried rebuilding the assembly (CTRL+Q) but still won't show any errors. The only reason that I noticed that I have errors is that I sent the file to a coworker and when he opened the assembly all the errors showed up. We have the same settings in the 'Systems Options' tab. Any idea how I can solve this?