I had a few issues upgrading from 4.9.5 to 5.5.1. However, after a bit of trial and error, I was able to perform the upgrade with no errors. Everything appears to be working for the most part. However, today I tried to copy a page and received the following error:

Error: is currently unavailable.
DotNetNuke.Services.Exceptions.ModuleLoadException: Tab Exists ---> DotNetNuke.Entities.Tabs.TabExistsException: Tab Exists at DotNetNuke.Entities.Tabs.TabController.AddTabInternal(TabInfo objTab, Boolean includeAllTabsModules) at DotNetNuke.Entities.Tabs.TabController.AddTabAfter(TabInfo objTab, Int32 afterTabId) at DotNetNuke.Modules.Admin.Tabs.ManageTabs.SaveTabData(String strAction) at DotNetNuke.Modules.Admin.Tabs.ManageTabs.cmdUpdate_Click(Object Sender, EventArgs e) --- End of inner exception stack trace ---

Any ideas what may be causing this?

Interestingly enough, changing to a different name worked. However, it took much longer than usual to copy the page. It seemed like about 1 minute. After the page was copied, I was able to go to the page settings and rename it to what I originally wanted to call the page when I tried to copy it.

Any ideas on what would be causing things to act this way?