Thanks to you all.

Yes I agree diferential is the best option, I don't have the mirror option.

I currently make full backup of PMAIL/MAIL/ADMIN at the same time I backup my Documents files on WIN 10.

I want to make more frequent backs, but as incremental backups to save time. That is, incremental for both PMAIL/MAIL/ADMIN and my Documents files at the same time.

Is it possible to recover my emails from the last full backup of PMAIL/MAIL/ADMIN followed by all subsequent incremental backups neccessary to recover to a working system? Or must I take a full backup of PMAIL/MAIL/ADMIN every time to be sure of a safe recovery?

Michael

I don't see any reason for problems with restoring from a full and then incrementals.  Insure Pegasus Mail is closed when backups are made.

FWIW, differentials are my preference for ease of restoration as compared with restoring from a full and then multiple incrementals.

Differentials, definitely!

Incremental or differential - this depends on your backup strategy. Both have advantages and disatvantages. There is also a third opportunity: "mirror", which we are using. A former complete backup will be compared with the current data stock and only changed data will be copied and updated at the existing backup. It is quite fast and you've got always a complete backup. This makes it easy to restore data without processing of additional inkremental backup.
We are using the free MS' command tool "robocopy" which also have a -mirror option, and hold 6 complete backups on 3 external harddisks which will be used in turn every week. Additionally we maintain a daily mirror backup at another server at local LAN.

I've been using AOMEI Backupper Pro but the free version works as good. I don't do selective data backup anymore mostly because hard drives are cheap nowadays. So, what I do is a full HD image and weekly differentials of what changed in between. It is very fast and all the process is done automatically with old chunks (whole HD and differentials) being replaced by the newer. I keep two full images with five differentials each. Backups are done to two external HD alternatively. I used another setup when I was doing daily backups.