I ran into problems today after my pc was updated with Acrobat Reader 11. I have Acrobat X Pro installed and use review tracking with the Adobe Collaboration Synchronizer (10.1).
When i opened the tracker, all my shared documents were gone. What I have found is that Adobe Collaboration Synchronizer 11.0 (installed with Reader 11) takes control of tracking. If i opened a shared review document and opened the tracker from there, i saw my tracker with all my reviews (v10.1). When i opened the tracker from the system tray, they were all gone (v11).
In the task manager, it showed 10.1 and 11.0 open at the same time. When i ended the process of 11.0 and double clicked the tracker icon, 11.0 was opened again and was the only one that could be viewed.
The only solution was to uninstall Reader 11.0 to get my tracker back again.
Adobe should have kept it in mind and existing reviews should have been migrated to the new tracker.
Update to Acrobat Reader 11 with caution!