Are you sure someone at work isn't accidentally playing with Beta to see what features are available?
This ^^^^, or is someone's machine set to download updates by accident, and is now 14/15/16? The only way you should get this message is if they either are in fact from a future version, or your machine thinks it's pre 2013 (rare, but possible if you have/had multiple versions installed). In the latter case, unsinstall all Solidworks versions and do a clean install.
if you can upload a sample file-
possible to check the true version on the forums
if you have a restore point from working models-
maybe do a disk image first- and try from that date
check your system for *.bak files of your problem files
copy and rename to specific test file and see what is
all I got at the mo-
hope this helps- have a good'n kelef
Thanks guys, I'll play around with your ideas a bit and see if I can resolve it. Il keep you posted, thanks for the help