I have inherited an Exchange 2013 CU9 server that urgently needs to be upgraded to CU23 for obvious reasons. I have already done this to another server in the exact same scenario (this one's partner in a DAG) and no issues, however this one is prompting for the CU9 install media in order to process the "uninstalling" stage. It's looking in C:\Temp\CU9, which does not exist, and the log reports
[ERROR] Couldn't remove product with code 4934d1ea-be46-48b1-8847-f1af20e892c1. The installation source for this product is not available. Verify that the source exists and that you can access it. Error code is 1612.
The other server, which upgraded fine, does NOT apear to have had the CU9 install media anywhere on it so I can't imagine why this one in particular must have it. Is there a way to bypass this, to force CU23 to perform the removal, or a way I can get my hands on the CU9 install media?