When Disk Defragmentation started, an error window "MMC cannot open the file C:\\\\Windows\\\\ystem32\\\\dfrg.msc occurred. This may be because the file does not exist, is not an MMC console, or was created by a later version of MMC. This may also be because you do not have sufficient access rights to the file." appears.
Here are some suggestions on how to fix running disk defragmenter problem in Windows.
One of the methods below should be able to help you restore Windows Disk Defragmenter. Try the first solution and then run Disk Defragmenter. If it didn't fix the problem, continue with the second one and etc.
Solution 1: Make sure you have rights to run Microsoft Management Console (MMC) and MSC file.
Solution 2: Go to Start > Run, type regsvr32 msxml3.dll and click OK.
Solution 3: Go to Start > Run, type regsvr32 dfrgsnap.dll and click OK. Then again go to Run, type regsvr32 dfrgui.dll and click OK.
Solution 4: Go to C:\\\\Windows\\\\Inf, right click at dfrg.inf file and select Install.
Solution 5: Go to Start > Run and type sfc /scannow. Make sure you have your Windows XP installation disc in the CD/DVD drive.
Solution 6: Download and apply .MSC association fix.
Solution 7: Download and apply Defrag SnapIn registry fix. Use SNAPIN method can solve other MMC issue, I've try at SGC AD roles migration from DC to ADC.
Solution 8: Download and install latest MMC 3.0 from Microsoft.
