Quartus error 13223 during synthesis on IP file generated by Quartus
I am porting a design from Quartus 16.1 to Quartus 19.2. I've followed the user guide and have cleared most warnings and errors and upgraded IP files.
One of the IPs generated by Quartus fails to load during synthesis and I get error 13223 "cannot open vhdl file" or "cannot open verilog file". The files are there and access permissions are OK. I can open the files and it looks like they're encrypted. But they should still be readable by Quartus, seeing as it generated them.
The help file is not very useful for this error code.
"ACTION: Edit the file to correct the error. A future version of the Quartus Prime software will provide more detailed information about this error."
I cannot edit an encrypted file. Is there any real solution to this problem?