Problem with Upgrade to beta 2

I downloaded beta 2 of Devonthink Pro Office 2. When I went to install, and tried to drag the program into the applications folder, an error dialog told me that the operation could not be completed because Devonthink Sorter was still in use. I clicked on Devonthink Pro on the dock, the icon changed, but the program wouldn’t launch.
I am stuck, I can’t start Devonthink, I can’t close the Sorter, and I can’t install the latest version.
Any suggestions?

Launch Activity Monitor (Applications > Utilities). Select any process that contains “DEVONthink” in its name, which will include the Sorter. Quit the process(es).

Now you can install the new DEVONthink2 release.