cannot open project, Says it's running already but unity isn't open

Recently I’ve been getting an error when trying to open my spitscreen fps project. It comes up with an error message saying that the project is already open, but unity isn’t open at all. Any idea what the problem might be?

Another way you could solve this if you haven’t already is by following the steps:

  1. Open the main project folder
  2. Enter the folder ‘Temp’
  3. Delete the text document ‘UnityLockfile’

You should be set. It happens alot with me, and this fixs it. When you close unity normally it deletes the file anyway. If it crashes, it may not delete the file. When you try to load the project, it sees the unity lock file (which is created when ever you open the project) and thinks that another unity must be running it.

I fixed the issue, the temp folder was corrupt so I had to shift everything over to a new folder

Hi @EliteHedgehog56,
Look like the unity process is still running, try open Task Manager find Process tab and kill Unity task.

Go to activity monitor and see if unity is running . if yes kill it .

This was happening for me since i invoked build through command line and that process was still running and but was not visible as open

I delete Temp folder in your project.