DF19.0 Studio RC2. This may not be an issue specific to 19.0 but thought you might want to know

Error:
Unable to access workspace lock file.
This workspace may be currently open in another Studio instance.
See the Output Window for further details.


.1. The workspace is not currently open in another Studio instance. (well not visible on the screen anywhere)
.2. What Output Window?
The Studio's Output Window is nowhere to be found - annoying.

I tried to erase ws\IdeSrc\Workspace.loc
This failed with the error
This process cannot access the file because it is being used by another process.

I exited Studio DF19.0 RC2
I tried to erase ws\IdeSrc\Workspace.loc
This failed again with the same error

I opened TaskManager, deleted all tasks on the Applications tab except the Command Prompt
I tried to erase ws\IdeSrc\Workspace.loc
This failed again with the same error

In TaskManager I clicked the Processes tab. I saw Studio.exe running as a process. Hmmm I thought. I clicked "End Process"

I tried to erase ws\IdeSrc\Workspace.loc
This worked!

Problem: Studio.exe was still running as a process with nothing visibly active on the screen. The workspace opened by this Studio.exe was locked out cuz the Workspace.loc file existed in a non-erasable state.

Solution: Make sure all Studio's are closed on the screen. Run TaskManager -> Processes and "EndProcess" any Studio.exe's still running.