Android : Syncexception: Directory Not Empty?

I have an emulator that it's snapshot is enabled.My App has no error,but some times when I want to test my App on that emulator,installation failed and I see these in console: and

Solution 1:

I restart emulator from snapshot then uninstall my App from it and try again and no problem occurs.I don't know caused this problem,but it seems to be solved in this manner.