Error 1921 is a common problem for Windows computers as it will continually prevent you from being able to install “Microsoft Office” and a variety of other programs onto your system. The error is basically caused by the “Machine Debug Manager” automatically running on your system – preventing your installer from being able to run properly. The way to resolve this error is to stop this service running, as well as to fix any of the potential Windows errors which may be leading the error to show.

The way 1921 error will typically show in this format when you attempt to install a program onto your PC:

  • ERROR 1921
  • Service ‘MDM' could not be stopped. Verify that you have sufficient privileges to stop system services.

The error you're seeing basically means that when your PC is trying to install your software, it's being held back because it cannot stop a particular service from running. Windows has a lot of “services” which continually run on your system – allowing Windows to perform a number of different activities such as keeping your Internet connected and keeping the “Start Menu” running. Although Windows services are required for your PC to run, they are continually causing your PC a lot of problems which need to be fixed.

The first step to fixing the 1921 error is to stop the “Machine Debug Manager” service from running. This is easily done by clicking onto Start > Control Panel > Administrator Tools > Services. When you click onto this option, it will load up a screen with the various services your computer has running. Through the list that it has, you should then look to find the “Machine Debug Manager” and stop it running. This will allow your installation to commence.

The second step to fix the 1921 error is actually the most important, because it's where you fix the various settings which could have caused the error in the first place. The problem that actually causes the error could well be down to a part of your system called the “registry” – which is a central directory of information & settings that Windows uses to run. Although the registry is continually being used to help your computer run as smoothly as possible, it's also one of the most damaging parts of your system – leading Windows to continually show various errors. In order to prevent the 1921 error occurring again, it's recommended you use a registry cleaner to scan through the registry database of your PC and fix the errors it has.

Source by James Henry Johnson