Last weekend, I pushed out an agent update from 2016.3 to 2017.3. In the process, the agent broke C++ 2013 on our core Commvault backup servers. This required a repair installation of C++ 2013. It didn't cause a lot of issues because it was caught quickly. Similarly, the Commvault agent on our Exchange server was failing to take backups. The reason ended up being the same. A repair installation of C++ also fixed this. Since we have already found the solution, I don't need a response to this. However, it would be great if this could be passed along to developers to work out any compatibility issues between the Landesk/Ivanti agent and the Commvault agent.
Just for reference, the error that displays when the backups fail or when the services fail to start is "The program can't start because mfc120u.dll is missing from your computer. Try reinstalling the program to fix the problem."
If I can provide any more information, please let me know.