One workstation stuck on "Adding the machine" when adding to AMS

I'm having issues with one of my workstations, trying to add it to the AMS. It gets through "Creating trust relationship" fine, but gets stuck on the "Adding the machine" stage. I'm logged in to the machine and am monitoring the mms.exe process, but I am not seeing the issue described in KB article 4695 with mms.exe consuming CPU and memory. That process isn't showing any activity at all.

I have even let it sit overnight at "Adding the machine" but when I get to work 15 hours later, it's still at the same point. I am able to remove and add other machines to/from AMS with no problems.

I'm running B&R 10 (yes, I know 11 is out). I'm not seeing any issues in the event logs. Only a handful of files in the folders in "C:\Documents and Settings\All Users\Application Data\Acronis\BackupAndRecovery\MMS". Not sure where else to look. I've even completely removed Acronis from this workstation and reinstalled, with no change.