Use the following steps for package reinstallation:
* Catalogue all applications active in the current ownCloud instance. Take special care to identify which "core" applications were activated and which third party applications were installed.
* Review and document all ownCloud sharing techniques used in the current ownCloud instance.
* Do backups of the ownCloud database and stored files.
 restore config from backups
 restore apps from backups
 restore database from backups
 login to admin as usual