I recently performed a migration of an Office 365 site to the upgraded Sharepoint 2013 format using the Public Website Content Migration App. I had a number of issues; so I thought I’d post the solutions.
The first issue I ran into is when running the app I received an error message of:
“Server Error in ‘/publicsites/migrationapp’ Application running the public site content migration”
I thought this might be an issue with the app so I tried removing it and re-installing it at which point I received an error of:
“Sorry, you don’t have access to this page trying to install app or trust app.”
I was logged in as a global administrator, so this access error made no sense. The root cause of the issue is I had installed the app and then didn’t finish the process during the same session. In order to resume the process I had to uninstall the app from BOTH the new and old SharePoint public sites. Once they had both been removed I was able to reinstall the app from the SharePoint store and both of the error messages disappeared and the upgrade completed without any issues.