Failed When I Tried to Upgrade Nexus2 repository to Nexus3

I followed the steps provided on ‘Upgrade Procedures’ to upgrade our Nexus2 individual repositories to Nexus3. I upgraded most of them successfully. But It got failed for one repository with exception ‘Failed: java.lang.IllegalStateException: Scan failed’. I tried this several times by increasing file descriptors to ‘65536’ and also ‘85536’. I attached a screenshot to this Topic. Please anyone can suggest some solution.

Have you checked the nexus.log files of both instances to see what errors occurred?

Thanks for your advice, I figured out the issue in Nexus2 logs. There was one artifact missing from the server but not deleted from the database. I rebuilt metadata and restart upgrading that repository, Now it is upgraded successfully.