Regularly it happens that you open a project and get this message:
Would be nice to have a third option here:
Similar problem in https://forum.mendix.com/link/questions/86584. The solution for me was to delete the .mpr.lock file. In windows you have to enable viewing of hidden files to see it.
How to solve this problem?
Tim, good idea, but..
.. in many cases this warning occurs when for some reason Mx Studio Pro is not closed correctly or when the complete Windows session is closed or has crashed.
The message seems to be triggered by the existence of a lock-file in the project folder. E.g. PostNL-Moas-Cleaning.mpr.lock
In that case there is no possibility to open "the other app".
Or when an app (on a shared folder?) is opened from another machine, there is also a .mpr.lock file and no possibility to open "the other app". In that case you should better not open the project anyway.