I am currently trying to upgrade a couple of our sites from SharePoint 2010 to SharePoint 2013. I was able to do our largest site without much issue, but two of our smaller sites are getting stuck when I try to mount the content database from the old site to the new one via PowerShell. Both are getting stuck at 15%. I am using the farm admin account, so permissions shouldn't be an issue. I have let this run for a couple of days before with no change in the percentage of the content databases.
Database One:
Size: 22 GB
Site Collections: 1
Database Two:
Size: 203 MB
Site Collections: 1
The only error in the logs I have seen refers to the old content database using classic windows authentication versus the new web application using claims, which I know would not be the reason it would be getting stuck, seeing as how the database I was able to upgrade had the exact same error, but upgraded successfully.
What else should I be looking at to see why this may be occuring?