Update from OH4.0.1 to 4.0.2 (docker) results in ERROR:HANDLER for 99% of openhab things

The files merely being present is not sufficient to indicate whether the add-on is installed. To see what add-ons and other bundles are installed and active use the karaf console. The Console | openHAB

bundle:list|grep -i dsmr

empty result. So could it be that we are not speaking about a problem of filesystem, maybe something in the registry where the bundles are registered?

I don’t know how that parts work. All I can recommend is removing and readding the missing add-on to see what changes.

What are the contents of your /openhab/conf/services/addons.cfg file?
If you use it for configuring add-ons it gets reapplied every startup.
So either add all your add-ons to this file or comment everything in this file and always use the UI for managing add-ons.

…in this file is all commented out:
docker exec -it openhab_openhab_1 cat /openhab/conf/services/addons.cfg|egrep -v '^#'
(empty result)
i had not to change anything and already managing on gui
the problem of lost addons is not appearing on every restart of the container. i had this 2 times. 1 time after update to 4.0.2 on the 16.8. and one time today. i restarted the container much more often. all about 1-5 days i have to restart