When attempting to Open my Elaborated design in PlanAhead, I receive the following error:
[Designutils 20-71] Top module library '<library>' not found
[Designutils 20-72] Failed to analyze HDL design
In PlanAhead tool, the Top Module Library is set under Project Settings > Language Options > Top Module Library.
In the Language options, this field is case sensitive, but the actual libraries are not. Therefore, if this field is entered with capital characters the actual library gets converted to lowercase even though the entry in the field retains the capital letters.
When "Open Elaborated Design" is then called by PlanAhead tool, the tools will not be able to find the version of the library containing capital letters.
To work around this issue, enter the top library name in lowercase letters.