When you try to change the master page for a Microsoft SharePoint Online site from inside the "Look and Feel" section of the site settings, you receive the following error message:
An Unexpected Error has occurred.
To work around this issue, follow these steps:
- Browse to the site where you want to change the master page.
- Create a subsite under the affected site.
- Browse back to the parent site that you accessed in step 1.
- Make the changes to the master page as needed.
- Delete the new subsite that you created in step 2.
This issue occurs after you receive the latest SharePoint Online service update. The product team is working to resolve the issue as soon as possible.
Article ID: 2796622 - Last Review: Feb 14, 2017 - Revision: 1
Microsoft Office 365 for enterprises (pre-upgrade), Microsoft Office 365 for small businesses (pre-upgrade), Microsoft Office 365 for education (pre-upgrade), Microsoft SharePoint Online