I have a large assembly made of of multiple sub assemblies, and there is one sub assembly that is causing issues when I open  the file I get the following error message. There is assemblies within the sub assembly that are missing.

I will suppress the whole sub assembly and then open that sub assembly individually and it opens fine with no issues. I then unsuppress the sub assembly in the main assembly and everything is when it needs to be.

I save everything and then try and re open the main assembly and same error message comes back.

I can't post the files for confidentiality reasons.