runtime error 21 at startup

When logging into windows XP I receive 2 pop up runtime error messages "runtime error 21 at XXXX49D2". The first 4 numbers are different every time I log in. The last one received was 03E549D2. With both pop up boxes the computer will not fully boot. If you x out of one box it will reboot and you can use the computer as normal. If you X out of both pop up boxes the desktop refreshes and starts over with 2 more runtime error pop up boxes!
I have also noticed that in the last month I have tried to install automatic updates on my computer and they have failed. I am not sure if that was related to my runtime error message. However, I just completed the express updates with no failures so maybe that is no longer an issue.
Can anyone help?

Question Info

Last updated March 25, 2018 Views 1,923 Applies to:

Hello imt4,

It sounds like you’ve got a program that’s interfering with both your updates and causing issues in your windows startup. In order to determine what is causing this issue we will need to use MSconfig to test what program is causing the error and then perform an uninstall/reinstall of the program to see if that repairs it.


Here’s the KB you can follow

This will help you diagnose what the program is, once you find out what it is you can simply remove it using add/remove programs from control panel and then change back to a normal startup. See if you’re still getting the errors, and then try the updates. If everything is ok, then you can try reinstalling the program, but if you still get the errors there may be an issue with how it’s installing.


Thank you,



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