You can delete the data via the backup storage tab in software GUI. Just right-click on any file/folder and select "delete".

That method appears to be VERY SLOW! In fact you have to wonder if the app is locked up. I see a dialog box saying "Initializing" and nothing seems to happen.

I was actually deleting from the "Edit Account" window. That is very SLOW! Is the Backup Storage window faster?

All of that depends on the amount files you have in the cloud. In some situations deleting data via native storage functionality is quicker, especially if you have a lot of files.

The problem here is that the Cloudberry app crashes or hangs, A LOT! So when the user has to abort Cloudberry backup and clean up the mess, is the backup corrupt? I have to assume that the backup is corrupt. So how do you delete the corrupt repository? Deleting the repository will hang too! Or deleting a small repository that is 50GB or so can TAKE DAYS!

I am not impressed with Cloudberry.

The files are not corrupted, the software will upload what it can before cancelling the job, beaning that all files that have been transferred to the storage side will stay there safely.

As for crashes, we would need diagnostic logs from the machine sent to us via tools > diagnostic menu to investigate that. Make sure you're on the latest version.

How can I tell if I am on the latest version? I have two different installations of Cloudberry backup for Windows with the same version that have a different user interface.

Seems like you're already on 6.0.2, so that's good.
To avoid confusion and creating additional threads here I suggest to continue in our ticket system.