In the event the local copy of the repository catalogue get corrupted the command
"pkg update -f" must be run. I propose a change to both the error message and the PKG-UPDATE man page to suggest this. User's having been googling for this answer since 2014. I started using FreeBSD with version 4.5 and never hit this error until updating from 10.3 --> 11.3. I also had to google for the answer.
Better yet, pkg should be able to detect this condition and perform the equivalent `pkg update -f` itself (unless `--no-repo-update` was specified).