Hi,
when moving a database (tasks.db for sqlite3) from one host to another please make sure that the OpenVAS Manager (openvasmd/gvmd) version on the target host (Hint: How to compare the current used versions of the OpenVAS/GVM packages with the GVM-9 stable release?) is at least on the same level like the original host.
e.g. you can migrate an manager 7.0.2 database to a version 7.0.2 or 7.0.3 but not a manager database from 7.0.3 to a host running version 7.0.2 of the manager without updating the manager version first.
It might be possible that you e.g. have migrated the database to a host running a higher version of the manager then previously used. In this case the manager won’t start and will log a note to its logfile (openvasmd.log/gvmd.log).
In this case you need to run the database upgrade routine like explained in the documents below: