Exchange 2010 Cumulative updates not installing ?

This was a piece of work during a migration where a client had an Exchange 2010 server that was missing the latest Cumulative Update Rollups. The client reported that attempting to install the update failed – with a message that it had ended prematurely because of an error.

The initial response was to try an earlier CU but this resulted in exactly the same message. Other intermediate CUs were tried but to no avail.

After some research I found that an alternative approach would be to invoke the msiexec installer from the command line in an elevated command prompt (open a CMD with Run As Administrator).

The syntax is

msiexec /update Exchange2010-KB2917508-x64-en.msp

where the update is the one you require to install.

Bearing in mind the update is likely to stop services – ensure you are doing this in a maintenance window not with live production servers.