PrivateKeyMissing when running Enable-ExchangeCertificate

Ran into an issue today where I could not get a certificate installed on an exchange server.  Was giving me "PrivateKeyMissing when running Enable-ExchangeCertificate.

I found the below instructions that fixed the issues for me.

https://support.comodo.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1188


Enable-ExchangeCertificate : The certificate with thumbprint XXXXXXXXX was found but is not valid for use with Exchange Server
(reason: PrivateKeyMissing).
At line:1 char:27
+ Enable-ExchangeCertificate -Thumbprint XXXXXXXXX -Services "IIS"

The above error can as a result of multiple reasons. CSR was created with IIS and attempted to be installed through the Exchange Management Shell (EMS), CSR was created in EMS on another Exchange Server, a damaged certificate, or Windows simply "forgets" where it placed the PrivateKey for the certificate. It doesn't happen all the time, but sometimes the error can be a nuisance.

Option #1: Repair Damaged Certificate (Windows Server 2003/2008)

1. Open MMC and add the Certificate Snap-In for the Local Computer account.


2. Double-Click on the recently imported certificate.
Note: In Windows Server 2008 it will be the certificate missing the golden key beside it.


3. Select the Details tab.


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


5. Open up a command prompt session. (cmd.exe aka DOS Prompt)


6. Type: certutil -repairstore my "SerialNumber" (SerialNumber is that which was copied down in step 4.)


7. After running the above command, go back to the MMC and Right-Click Certificates and select Refresh (or hit F5 in the MMC)


8. 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."
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.


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

Option #2: Remove and Re-Install Certificate (Windows Server 2003/2008)

1. Verify the certificate doesn't have it's private key.
   In the MMC and double-click the recently imported certificate. (Be sure that you're using the Certificate Snap-In for the Local Computer account!)
Note: In Windows Server 2008 it will be the certificate missing the golden key beside it.


2. Right-Click on the certificate and click Delete.


3. Re-install the Certificate