Recently I faced a problem, that in SharePoint Designer (2010), one of my file I checked out and then I checked Inn. Again when I opened my SharePoint site in Designer, it was showing the same file as checked inn. So I thought I might have forgot to check Inn. I again tried to check Inn, but it promt me an error message :
" Cannot peform this operation. The file is no longer checked our or has been deleted "
Solution:It is because of the cache being mantained with respect to user websites and application data.
What you have to do is, go to following locations :
- %APPDATA%\Microsoft\Web Server Extensions\Cache
Hope this help!!