You may want to review this article: https://confluence.atlassian.com/pages/viewpage.action?pageId=412483920
As this appears to be an issue with your Microsoft SQL Server database collation. This should help assist you with properly completing the upgrade procedure.
Chuck Talk | Confluence Support
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG