I am trying to upgrade Jira from 7.3.2 to 7.8.2 on a Windows Server 2012 64-bit server. I always run the installer as an administrator. During the installer I got an error, "could not delete C:\Program Files\Atlassian\JIRA\jre\lib\charsets.jar". No one is in the server but me, and I'm pretty sure nothing is using this file. I clicked retry a few times, but that did not resolve the error. So I clicked cancel.
I tried to run the installer again, upgrade an existing Jira installation, but now it claims my existing Jira directory is not a valid Jira Core installation directory.
What should I do? Please help!