Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I regularly see this error in the Windows Error Log on one of my EC2 instances:

Certificate for local system with Thumbprint aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa is about to expire or already expired.

It appears EC2 uses a self-signed certificate to communicate with an Active Directory service somewhere on the EC2 network. It uses the certificate above to communicate with this, and tries to auto-renew periodically. It appears this mechanism has failed.

  1. What problems can arise from this?

  2. How do I fix this?

I attempted to follow the instructions here:

But the certificate is not found - the Thumbprint is either an MD5 or more typically SHA1 hash. I searched for both criteria in mmc/Certificates and none were found.

How do I resolve this, and how problematic is it?

share|improve this question

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.