An update of the UCS system fails. In the /var/log/univention/updater.log you can see entries like this:
Errors during processing of /var/cache/apt/archives/emacs24-common_24.5+1-11+deb9u1_all.deb E: Sub-process /usr/bin/dpkg returned an error code (1) Error: Failed to execute "apt-get -o DPkg::Options::=--force-confold -o DPkg::Options::=--force-overwrite -o DPkg::Options::=--force-overwrite-dir --trivial-only=no --assume-yes --quiet=1 -u dist-upgrade"```
Attempting to restart the upgrade procedure leads to the same error but possibly with a different package.
Disable your virus scanner during upgrade process.
For Sophos do:
systemctl stop sav
Perform the upgrade and re-enable your virus scanner.
Note: There are only very few Linux viruses seen. If you do not use the KDE app you should configure your virus scanner only to monitor the shares for Windows clients and exclude the system directories.