OMV doesn't boot after remove of hdd

I have an running and working OMV 3 - no problems so far.

Now I wanted to remove one storage hdd and run into a problem - not sure if this is an Debina or OMV Problem.
I removed everything in OMV (shares, settings ...)

cd /etc
find . -type f -exec grep -l "id-of-my-hdd" {} +

didn't find anything besides some leftovers in the omv cfg (testwise removed)

If I reboot I got his message ->

it complains about an disk which is connected and running, after the test it drops me into the emergency mode

journalctl debugs

If I shutdown and connect the dropped out hdd it boots perfect.

Any Ideas where too look ?