Run Cleanup before new backup

Rhys, welcome to these public User Forums.

To be honest, you would be best advised to invest in a larger backup drive given how inexpensive these have become.

ATI works on the principle of not deleting any old backups until a new one has been created successfully.

If you were to force the delete of one of your older full versions before creating a new one, then it is very likely that your backup with throw up errors for the missing files.

In addition, if you will be upgrading to ATI 2020 or later at some time in the future, then any method used to delete your older full version files will be broken because of the new file format introduced by Acronis which changes the way backup chains are handled.

keep 2 full versions, but delete the oldest before starting a new one

You could submit a Feedback requesting this feature.

As Steve said, this goes against the current Acronis philosophy of not deleting backups until a new one has been successfully created. I believe the function you want is supported by some other products, and Acronis would certainly rather have you stay with Acronis products, but I think they would need a very persuasive argument in order to change this philosophy.

A potential problem with the "delete first" idea is that something could prevent the new backup from being successfully created.