Why Visual Studio Team System 2008 try to check out all solution's projects while debugging?

We develop using VS2008 solution that have about 26 project that's added to Team System Source control.

The problem is: sometime when developer try to debug a project, VS check out all projects before debugging, we don't know Why this happen especially if we close all vs and try again the开发者_StackOverflow problem not appear ... Is any know how to solve this issue ?

That's how it is. I hate it too. The best you could do is configure Visual Studio to ask every time before it checks out a file so that the developer is being warned of what is happening behind the scenes: