I was trying to renew my UCC certificate for my Exchange 2010 server. All was going fine until I tried to enable the certificate. I got the following error message:

Enable-ExchangeCertificate : The certificate with thumbprint *** was found but is not valid for use with Exchange Server
(reason: PrivateKeyMissing).
At line:1 char:27
+ Enable-ExchangeCertificate -Thumbprint *** -Services "IIS"
  1. Open MMC and add the Certificate Snap-In for the Local Computer account.
  2. Double-Click on the recently imported certificate.
  3. Note: In Windows Server 2008 it will be the certificate missing the golden key beside it.

  4. Select the Details tab.
  5. Click on the Serial Number field and copy that string.
  6. Note: You may use CTRL+C, but not right-click and copy.

  7. Open up a command prompt session. (cmd.exe aka DOS Prompt)
  8. Type: certutil -repairstore my “SerialNumber” (SerialNumber is that which was copied down in step 4.)
  9. After running the above command, go back to the MMC and Right-Click Certificates and select Refresh (or hit F5 in the MMC)
  10. Double-Click on the problem certificate. At the bottom of this window (General tab) it should state: “You have a private key that corresponds to this certificate.
  11. Note: In Windows Server 2008 there will be a golden key to the left of the certificate, so there is no need to double-click the certificate.

  12. Now that the Private Key is attached to the certificate, please proceed to enable Exchange Services via Enable-ExchangeCertificate.