Thanks. I tried to understand your reply by studying the documentation (Install and config guide), but it appears to be very out of date as the screens and options do not match. Some points:

- Note that I am using a File Backup (legacy) plan. When configuring this, my schedule selection is Reoccurring (predefined templates), next screen Custom schedule template set to Incremental every 2 hours and no block levels. Summary text box reflects the plan correctly as 'Incremental backup: Occurs every 2 hour(s)'. The final Summary screen shows 'Block-level: Occurs every 2 hour(s)' however. I've checked my backup storage and all file backups appear to be Fulls - no Block indications. So... I believe that my incrementals are file-level (as specified) and that the block-level indications are false.

- I played with File Backup (non-legacy) and see where the schedule option never asks for incremental vs. block backups. Is this where you are thinking that incrementals are block-level by default?

Thanks!

In the end, there didn't seem to be an answer to this issue. It was likely caused by an import of a very old configuration file from my previous machine.
I deleted all the backup plans and made new ones. The existing backups were successfully connected to for the plans which used legacy file backup - the backups continued where they had left off. The one backup that I had set to use the new (non-legacy) file backup format wanted to backup all files again.

I tried the cloning when it first happened and the dup plan had the same issues. The plan was created with the same software (desktop/Windows) and version and on the same system. But in my long journey to move to a new system, which really has surprised me with many issues, I did do an import of a plan created by a really old version on the old system. Perhaps that's where this issue started. I will explore further or just start from scratch.
Thanks so much for the help David.

Ya, meant to include that... 7.1.3.28