Dialogs Become Shy following Site Restore

I came across this following restoring a site collection the other day. When I selected an event item I received the message “The website declined to show this webpage” (see image below) – how rude !

The event item in question contains managed metadata. As we all know managed metadata is synchronised to a hidden list within the site collection aptly named: “TaxonomyHiddenList”. This list does not inherit permissions thus the security for the list was invalid which explained the curt response from the dialog framework.

I resolved the issue as follows:

Navigate to <sitecollection>Lists/TaxonomyHiddenList/ and follow the following six easy steps:

1. Navigate to the "Pemissions for this list"
2. Select Inherit Permissions
3. Select Stop Inheriting Permissions
4. Add Authenticated Users (NTAUTHORITY\Authenticated Users) with Read permissions
5. Update the System account (SHAREPOINT\system) to have Full Control
6. Remove all other users