A little while back, I ran into an interesting little problem after uninstalling and then reinstalling SQL Server 2012 on the same machine. In order to record a nice, pretty demonstration of installing SQL Server 2012 on a test machine for one of my Pluralsight courses, I decided to completely uninstall SQL Server 2012, and then reinstall it as I recorded it for the demonstration.
After I did that fresh installation, the SQL Agent Service would not start. All the normal troubleshooting measures gave me no immediate resolution. This was what the Windows Application Event Log had to say about it as shown in Figure 1.
Figure 1: Windows Application Event Log Details
This looked like a Windows Registry permission issue. Finally, I figured out that I needed to delete the old SQL Agent error log file (SQLAGENT.OUT), as shown in Figure 2.
Figure 2: Windows Application Event Log Details
After I did that, the SQL Agent Service started working just fine. I realize that most people won’t be uninstalling and then reinstalling SQL Server 2012 on the same machine that often, but just in case you do and you run into this issue, this is one thing to try out.