When trying to add relations between parts in an assembly, you might come across the error “Cannot use selection. Allowing this selection would create conflicting context.”
This happens usually because the sketch or feature that you are editing already contains relations with another part within the assembly.
There are two ways to solve this issue:
- Remove previous references to avoid conflict.
- Go to System Options>External References and check on Allow multiple context for parts when editing in assembly.
While the second option seems useful to quickly fix the issue, please keep in mind to be extra careful when using this option, since it could get tricky if you have too many multiple context between several parts in an assembly.