A few days ago the UR3 for DPM 2012 SP1 was released together with a few other updates (also for VMM, SCOM and AppController). A few days after it seems that a number of people have had issues with this UR3 update.
Issues are not completely clear yet, but seem to include things like not being able to upgrade the agent and not being able to delete or mofiy the membership of a protection group.
This issue is already being taken care of by the DPM team currently. In the meantime they have pulled the update down. I assume we will soon get information on a fresher version of the same and guidance on what to do if you are affected already. This is a message in the comments of a few blog articles from the DPM team:
We are actively working on the issues that have been reported here. We have pulled down the update from Microsoft Update. Given the issues seen at this point we would strongly advise against any further installation of Update Rollup 3 for DPM 2012 SP1.
We will shortly update you on the issues and the next steps. Stay tuned.
– DPM Team
As soon as I hear more information on the issue or if and when it is fixed I will update this post of course.