I'm a little confused as to what is happening with my Master Page.

If I check out the .master and reupload it without making ANY changes to the file, I get an error saying one of the declared Controls is not a 'Safe Control'. Any page using that MP becomes inaccessible. In order to resolve it, I need to reset my Master Page to Site Definition.

How do I make changes to the Master Page if it breaks when I upload it? I'm not understanding how this is happening.

Also, in SharePoint designer, I cannot see the master page gallery or 'All Files', not sure if this is related but was probably setup to not allow editing in Central Admin

  • What version of Sharepoint are you using, Foundation or Server? The control that is getting prompted as not a safe control, is it custom? Jan 28 '15 at 20:54
  • 2013 Server. It is a custom safe control. But how does it break when no changes are made? Only uploaded Jan 28 '15 at 20:57
  • Instead of making changes in .master file, try making changes in .html file and upload it and then publish.
    – Amit
    Jan 29 '15 at 4:19
  • They didn't use the new 2013 HTML standard. Just the .master exists Jan 30 '15 at 15:32

Perhaps your issue has something to with something SharePoint Designer is doing. Try resetting the master page to the site definition, then download a copy of your master page from the master page gallery using the web UI. Rename the file and make a minor modification and upload it back via the web UI with the new name. Then select the new master page in the site settings as the one you want to use. If all goes well check in and publish the new master.


Check if the safe control entry is there in the web.config, if not, add it, then the masterpage should work. Basically when you "edit" the masterpage you are unghosting it and that causes the Sharepoint to use type-safe parsers for all unghosted content.

  • I don't have access to the server to change the Web.Config. But the unghosting makes sense to me..Although I thought this only happened when editing in SPD not uploading through the Web UI Jan 28 '15 at 23:40

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