Unfortunately the IDE 2.0 does not honore the "portable" Subdirectory!
With testing I damaged my working environment, as I assumed, that all installations/changes go to the portable directory, as it was usable with all previous versions.
Especially for testing a portable installation is a must.
Stopped testing so far 
Hi @safdsaf. Thanks for taking the time to try the beta stage Arduino IDE 2.x and share your valuable feedback.
The lack of support for portable mode is a known deficiency that is being tracked here:
Even though Arduino IDE 2.x is not yet a complete replacement for the classic Arduino IDE, and certainly not yet ready for a production release. Arduino decided that it would be beneficial to release it in a beta state to allow the community to contribute to the project, in the spirit of open source. This project is under very active development, so I think that you will see a lot of progress happen in each new release.
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