I try to post here because it's omv and cockpit related.
I successfully installed cockpit on omv 4. The problem is that if if click the refresh button on the Applications tab in cockpit I get this error:
E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/cache/app-info -a -e /usr/bin/appstreamcli; then appstreamcli refresh-cache > /dev/null; fi'
E: Sub-process returned an error code
If I remove 'appstream' and 'autoremove' the rest and then do an 'apt-get update' everything is fine. As soon as I do an refresh on the Applications tab in cockpit, although there are no application to be installed, it looks like 'appstream' and its dependency get reinstalled.