Hi everyone
This is a beginners question and the answer may be totally obvious for the seasoned Solidworks user.

I imported numerous CATIA assemblies into solidworks and saved them each separately. Then I started to work these assemblies into one single large assembly by the command 'insert assemblies'. With all the parts and assemblies in the right place I saved the file. When reopening the file however the error 'unable to locate assembly file' message pops up although the file path and file name are all correct.

What can be the reason?? Is there something I missed when assembling assemblies?

Edu ​​​​​​​3DEXPERIENCE ​​​​​​​SOLIDWORKS ​​​​​​​