Developer’s personal settings and preferences are stored in a .user file. This is why it’s not recommended to add .user files to VSS or other Source Control tool – keep personal to yourself.
However, when using ClickOnce deployment, the published version is stored in YourExeProject.csproj.user. So, if you don’t check this file into VSS, when somebody else (or you on another computer) will do the ClickOnce publishing to the deployment server, the version number will restart from zero! Needless to say, that will mess up your versioning… You could manually enter the version you want, but many don’t... So, if you’re using ClickOnce with version auto-increment, do add your csproj.user file to the solution and check it into Source Control tool.