Full back up scheme

I have been using Acronis True Image to back up my C: drive for several years now. I had the occasion to successfully restore my C: drive just a few weeks ago. However, something changed in my backup scheme and now I am getting a "disk full" error message. I have an existing backup designated as "DESKTOP_1POST 1_FULL_b133_s1_v1.TIB" which only takes up 140.5 GB and leaves 145 GB free. So I should be able to add another 140 GB backup to the same external drive. Nevertheless, about halfway through the backup, I get the "disk full" message. I can't remember how I set up the original backup scheme so that I could get two backups on the same 279 GB external drive. Can someone help me figure out how to restore my backup scheme to accomplish this?
Acronis Links : Acronis Scheduler Manager : Acronis VSS Doctor : Backup Archive Compatibility : Cleanup Tool (All versions) : Cloning Disks : Contact Acronis Support : Difference between Backup and Disk Clone : Repair program / settings
MVP Assistant (Log Viewer) latest version see pinned topic in ACPHO forum page.
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