I had to wipe my existing OS and had to reinstall Nessus on the new BT5R3 image. However, I still wanted all my previous scan data and users to be unaffected in the new OS. So how did I do that? Here’s how:

Take a backup and restore the following folders on the new install:

1. Users Folder (/opt/nessus/var/nessus/users)
2. Master.key (/opt/nessus/var/nessus/master.key)
3. Policies.db (/opt/nessus/var/nessus/policies.db)

If you do get an error after this follow these steps to get rid of errors and just reactivate the nessus feed as follows:

1. service nessusd stop
2. /opt/nessus/sbin/nessus-fix –reset
3. /opt/nessus/bin/nessus-fetch –register [activation code]
4. /opt/nessus/sbin/nessusd -R
5. service nessusd start