The process cannot access the file Temp\UnityLockfile becuse it is being used by another process

Fist time using Plastic. Trying to shift from Collaborate to Unity Plastic.
When I press Checkin in Plastic or in Unity,
As shown in this pix an Error pops up:

In my case, is not guiclient.conf but the path is my project\Temp\UnityLockfile

I try to follow all the videos for this task but was not simple.
I do not know what to do now, how to go on.

Thread: Do I need to uninstall the Plastic asset package, delete the workspace and try again as a new project? Anyway for Unity users what is the latest best way?

I end up deleting the repository and deleting the hiding .plastic folder from my project