A problem that I have faced and it toke me quite period of time to figure out the reason of it. The case was that when running any Administrative Consoles MMC such as Active Directory users and computers , event viewer , or any other console I received and Access denied message Although I was using the Domain Administrator user Account. But I could run the MMC if I selected runas and provided the same credential. Initially I thought the problem is due to Virus infection of server , but after searching I discovered that i get this error due to miss association of MMC extension to notepad. The solution was pretty simple.
- Right Click any MMC
- Select Open with
- Click Browse and select c:\windows\system32\MMC.exe
- Select always use the selected program to open this kind of files