what is error code 0xc000012d ?

what is error code 0xc000012d ?

Question Info

Last updated April 19, 2019 Views 28,435 Applies to:
what is error code 0xc000012d ?

Basically, it means that the application failed to start/initialize properly.

Where and when are you getting this error? Are you referring to Microsoft Security Essentials, the topic of this forum? If so:

What operating system and service pack?

Prior Security Software?

Any security software still installed?

A possible reason for this problem is that you have conflicting security software installed fully or partially on the PC. Remove all other security software from the PC.

You may need to use a cleanup tool to remove your prior security software:


Be sure to review this post: Check list for installing Microsoft Security Essentials


If that fails to resolve the problem, open an email support case:


To open an email support case, start here:




Windows Insider MVP (Security), Moderator Microsoft Community

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