A couple months ago, one of my VS solutions would just crash with a specific project. After a couple of hours, I've found the solution: close Visual Studio, delete all the "*.csproj.user" files, and reload the solution. My theory is that this was caused by TFS merges, since this solution had a few dozen projects and was frequently updated by various users, which in turn caused frequent conflicts. It's no wonder that these files are listed in .gitignore.
Note: this is basically a repost from my previous blog.