I started with a clean, fresh OH3 installation on my rPi. I thought it would be easy to restore my OH2 configuration, but after restoring my latest OH2 backup file (without any errors), the items are restored fine, but all my things are gone.
I know, the is a lot information about this problem, but it is overwhelming and I’m still stuck.
Can anybody help me?
How did you back it up and how did you restore? OH3 uses different directory names than OH2.
You’ll have to install each of the bindings to which your ‘old’ Things should attach.
I backuped and restored with the standard OH tool. Restore went successfull without errors.
Ok. I suppose before restoring an that the bindings need to have the original names and ID’s. I’ll try today…
Thanks.
It will only patch your data from OH2 to OH3 if you do an upgrade. If you restore OH2 data in OH3 it will not patch it. See Upgrading:
If the install of openHAB 3 detects an existing openHAB 2 install, then it will copy the configurations across and update using those files. There are several major differences between openHAB 2 and 3 which may mean that this will cause issues, let us know if you experience anything strange.
My OH2 crashed, but I kept my daily backup files (created with the OH backup script) in a safe location. Do you mean that if I install a fresh new OH3 (openhabian), these OH2 backup files are useless?
I would guess in stall OH2, restore your data, & then upgrade to OH3
I will give it a try… 
It worked. Restoring into OH2 was the solution. Thank you.