You’re attempting to upgrade Microsoft Exchange Server 2016 from CU8 to CU12 but the process fails at the Prerequisite Analysis with:
Setup can't continue with the upgrade because the mscorsvw (3152) has open
files. Close the process, and then restart Setup.
For more information, visit: http://technet.microsoft.com/library(EXCHG.150)/ms.
This error is typically thrown shortly after a server restart when the .NET framework’s Native Image Generator Technology (NGEN) is running in the background. It is not a good idea to try and terminate the process and waiting for around 10 minutes is usually enough time for the process to complete depending on how fast the server hardware can complete the operations.
For the environment in this example, it took about 8 minutes for the installer to successfully run: