Unexpected error when creating a
new web part page in site pages on SharePoint 2013 site
Issue: Unexpected error when creating a new web part page in
site pages on SharePoint 2013 site
Cause: the error should be because of any faulty web part in
the site.
Solution :
1. navigate to the web parts maintenance page be
following.
by typing ?contents=1 after aspx
site page url
Ex:http://expertsharepoint.blogspot.de/aspx?contents=1
2. remove
the faulty Webpart
I hope the above information will help you to resolve the issue, in case of any queries/questions regarding the above mentioned information then please let me know. I would be more than happy to help you as well as resolves your issues, Thank you.