Living on the bleeding edge means we have to bleed occasionaly so I wasn't totally surprised when my modeling project wouldn't load under the VS2010 Release candidate - but I was concerned about the hemorrhage this was causing as I not only had days of work invested in UML diagrams for my personal project (http://ehr.codeplex.com/) but also weeks of work invested for my current contract.  

So when a co-worker told me about the Microsoft Visual Studio 2010 Architecture Model Upgrade Tool I was ecstatic!   I was relieved when upon upgrade completion I found that all of my diagrams opened up - I was now able to continue forward instead of losing countless time rebuilding old diagrams from print-outs.

Note: I did have some inconvenience during the first upgrade and used lessons learned to streamline the second.   Some tips follow:

1.  I didn't keep the default install path.   I selected the root folder of my documentation (Modeling is the Beta 2 and ModelingRC was the new diagrams moving forward).

2.  Since I was under source control on both projects I was sure to reset the readonly flag on all files in the Beta 2 Modeling folder (the second time).   Since I couldn't "check out" all files from the solution because I couldn't load the project to do so - my first attempt failed to upgrade because the files were readonly and I ended up going back and forth until I got through all of the failed files.   

3.  By installing to the root folder I was able to use the /upgrade /recursive command line which simplifies the switches required to run the upgrade utility.  

 
Note: I had to insert a space between /upgrade and /recursive