DCom Server Process Launcher (DComLaunch) service was introduced in Windows XP SP2. One of the major side-effects user face after disabling the DComLaunch service is that the Disk Defragmenter console fails to operate. The Analyze and Defragment buttons do nothing. Also, launching the console Defrag (defrag.exe) utility causes the following error:

Windows cannot connect to the Disk Defragmenter engine

The above tip was published in Snakefoot site, and the credit goes to them. It looks like they have moved to a new domain
Another side-effect of disabling DCOMLAUNCH.

The Windows Firewall service in Windows XP Service Pack 2, in Windows XP Professional x64 Edition, in Windows Server 2003 SP1, and in x64-based versions of Windows Server 2003 cannot start if the DCOM Process Launcher Service is disabled

Here is how to enable the DCOMLAUNCH service:

  • Click Start, Run and type Services.msc
  • Double-click DCOM Server Process Launcher
  • Set its startup type to Automatic
  • Restart Windows

Know more about the new DCOMLAUNCH service.