security - Windows 8.1: administrator account has access denied to other partitions

UAC is activated for the administrator.
With Windows 8 everything is okay.
After the upgrade to 8.1, the administrator account is denied to access the every partition except the one containing Windows, Users, Program Files, etc.

The message is the same as when a regular user is denied access to whatever folder.
It is impossible to see and change ownership and permissions.

Same error for every user belonging to the Administrators group,
even a user created for the test after the upgrade.

When we deactivate UAC for the administrator, access is okay.
But then we can no longer perform some actions, so UAC is important for us.

Update:

• the permissions already grant full access to the Administrators group


• chkdsk reveals no error

Answer

You may have restricted the permissions on your partitions to keep access only for administrators.

If this is the case, you face a Windows's bug. This bug is since Windows 7 I think. Seems nobody found a clean way to avoid it. Some people sais this is a bug into Explorer, but the command line exhibit the same behavior, as PowerShell, as other applications I tested.
It only fire when UAC is enabled and you belong to the Administrators group and the folder is restricted to the Administrators group only.

If you want to keep UAC, you have to modify the permissions to allow someone else to read the folders you want. Remember: this user must not belong to the Administrators group.
Personaly I create a special user for this usage only.

To modify the permissions, you may have to disable UAC. Once done, you enable it.