If you have two or more projects open, for copying, there could be a memory leak if both have been debugged. You are probably not notified of orphaned files when recreating a project. When copying a backup project to replace a project in another location you would be asked whether to overwrite files. This would be the easiest way to remove orphaned files; by deleting the project again. These files would not be visible in explorer if the project were deleted but an explorer search for the project would probably find the orphaned file. Unless you are certain of how to deal with dependent files such as interfaces it is best not to rename, but recreate.