Recently, we release a new version of our product and created a branch of our main source tree. Last week I made a change in our development branch that I needed to merge into our release branch as well.
Using the merge wizard in the Team Explorer from Visual Studio 2005, I tried to merge the changes into the release branch. Selecting the source path, destination location and the correct change set, I executed the merge action. It failed with this error:
It took us a while before we could solve this problem. It turns out that when the files to which the changes are being merged don’t reside on the local disk the merge action fails.
So whenever you receive the cryptic error message as shown above, make sure the files you are merging to are available on disk.
Hope this helps.