When updating the ADMX Central Store from Windows 10 to Windows 10 v1511, you may encounter the following error when attempting to view or edit group policies:
A similar problem is referenced in KB 3077013 but basically also applies to this issue:
If you are not using anything from the WinStoreUI.admx template, you're done. If you have configured settings that use the template (Windows Store), you will have to perform the following steps as well in order not to break the group policy in which they are configured:
Although you could ignore the problem, note that this will break the group policy Settings view in GPMC.