We just completed the upgrade from 5.1.0 to 5.1.1 this morning. Make sure that you also apply the hotfixes, from last week, hf983758 & hf988208. It took us a long time to actually do the upgrade as we ran into issues on our test server with the patch rolling back. Luckily, the servers are Virtual Machines so we could revert back to a previous snapshot. We had to engage our Platinum support who showed us how to fix the issues.
1. We had to run the patch setup.exe in a Command Prompt (Run as Administrator) with this command setup.exe DEBUGOUTPUT=2 . This stops the setup from rolling back and allows you to see why it failed by looking at the McAfee MSI install log under %temp%\McAfeeLogs
For us it looked like that Tomcat was starting up quick enough causing a timeout. Second error was related the the agent update key. We had to look for a line that started with RemoteClient and paste this command into a command prompt.
You may not see the issues we had as this is the first time I have ever seem patch issues. Have dealt with ePO since version 3.5.
Thanks twenden! This is very detailed and will surely help us when we encounter the same issue.