I just now tried to defrag my C-drive for the first time since I upgraded from Windows XP SP2 to SP3. dfrg.msc does not launch. Instead, I get an error popup with the following message:The procedure entry point?InterfaceMethodException@BookKeeping@@SGXHPBG0KPAU_EXCEPTION_POINTERS@@@Z could not be located in the dynamic link library mmcbase.dll1 person needs an answerI do too

That is exactly what happens when the c:\windows\system32\mmcbase.dll does not match the installed dfrg.msc.The dfrg.msc is looking for a function (an entry point) into the mmcbase.dll file and is not finding it. It sounds like your mmcbase.dll file is still SP2 era.The mmcbase.dll comes into play with the Microsoft Management Console functions so other things would not be working either - like Event Viewer. Do you get the same message if you open the Event Viewer by clicking Start, Run and in the box enter:eventvwr.mscClick OK and see if you get the same message...You can search your system for mmcbase.dll and perhaps find the correct version (look for a later date and it is about twice the size of the old one: ~163K), expand one for your XP SP3 installation CD, email a copy to yourself from another system or copy the file via a USB device from a working system, and just replace it and that may get your stuff working, but I would wonder if there are some other problems that you do not know about.Don't guess what the problem might be - figure it out and fix it. I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!

Yes, I got the same problem with Event Viewer.I located a larger, newer mmcbase.dll in [C:\WINDOWS\ServicePackFiles\i386]. I renamed the smaller, older file mmcbase.dll-SP2. Then I copied the larger, newer file from [C:\WINDOWS\ServicePackFiles\i386] into [C:\WINDOWS\system32]. Now, when I try to launch either Defrag or Event Viewer, I get an error popup that says:"Class not registered". What is the specific command for registering a .dll file?

In a Command Prompt window (or Start > Run) regsvr32 <dllname>You might want to unregister it first and then re-register: regsvr32 /u mmcbase.dll regsvr32 mmcbase.dllIn fact, you might want to take the new file out of system32, put the old file back into system32 under its original name, unregister it, then rename the old file as you did, put the new file into system32, and register that one. This is probably overkill, but ...

When I tried to unregister the .dll file, I got an error popup with the message: "mmcbase.dll was loaded, but the DllUnregisterServer entry point was not found. This file can not be registered." I then tried to register it and got an error popup with the message: "mmcbase.dll was loaded, but the DllRegisterServer entry point was not found. This file can not be registered." HELP!!!

I do not have that situation in my notes and have been unable to reproduce it. I wonder if (since the one DLL was old), if something went wrong with your SP3 installation. If that one file is out of date, there could be others.That DLL is not a registerable DLL, does not need to be registered and therefore is will not unregister or register. It is not a registerable DLL in the list of XP DLLs that need to be registered. That is why I did not suggest trying it - it will not work. I am not a tryer.If you rename or delete the DLL from the system32 folder, Windows File Protection will recognize it as one of the 3498 files that XP cares about and immediately and silently replace it with what it thinks is the correct version (before you have a chance to do anything else). You should make a copy, then copy what you think is the correct one over the top of the current one. Replacing these files in system32 is a little different than what you would expect for other files.After you copied in the "good" DLL from the servicepackfiles\i386 folder (that would be the right place to get it), did you reboot?There is something else wrong and I don't know what it is.Don't guess what the problem might be - figure it out and fix it. I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!

Install or reinstall the latest Management Console (3.0) and it will take care of file mismatches and dll registrations.Microsoft Management Console 3.0 for Windows XP (KB907265)http://www.microsoft.com/downloads/en/details.aspx?FamilyID=61fc1c66-06f2-463c-82a2-cf20902ffae0John

I tried installing the Management Console from the link provided by John. I got the message that it would not install because the version I already have is later. As a separate, earlier issue -- that I could not run Management Console -- I had reverted to the Windows XP SP2 versions of mmcndmgr.dll and mmcbase.dll. I was then able to run Management Console. After restoring the Windows XP SP3 versions of those files, I can now launch and use Defrag and Event Viewer. However, the problem with Management Console has returned. When I try to launch it, I get an error popup with the message: "MMC failed to initialize because it was installed incorrectly or becausea portion of the registry has become corrupted. Make sure the fileMmcndmgr.dll is registered by running"regsvr32 %SystemRoot%\system32\mmcndmgr.dll".I do run regsvr21 and then reboot Windows XP. That does not resolve that problem. PLEASE do not respond to this Management Console issue here. I will start a new thread for it. I consider this thread resolved.