Synced files seem corrupted after upgrade to owncloud 5 version

I just upgraded my owncloud community version from 4.5.7-1 to 5.0.3 with the effect, that I can’t read any of my files in the sync folder anymore! All seem to be corrupted. If you have the same problem, continue reading and find out how to solve it. Continue reading “Synced files seem corrupted after upgrade to owncloud 5 version”