Ok, so I had a large master assembly drawing constructed using many separate part's drawings all contained within the same network folder.
All files were behaving as expected.
I needed to produce some sub-assemblies from the master. So I opened the master assembly, deleted the parts I didn't require for the sub-assembly
and then saved that sub-assembly to a new location under a new file name.
Everything appears fine with the new sub-assembly but now when I open the original master assembly I am prompted to rebuild the assembly, after clicking OK, 75% of the master assembly has disappeared.
Why is this?
How can I restore the original master assembly file structure?
Thanks for your time.