Time Machine back up

[c1defence]

Time Machine keeps, or is supposed :
Local snapshots as space permits
Hourly backups for the past 24 hours
Daily backups for the past month
Weekly backups for all previous months
It also states that the oldest backups are deleted when the disk becomes full.

The back up size is 860 GB, and the HD are 1TB.

But I am receiving this on two external HD:

Time machine couldn't complete the back up

The backup disk needs 420.31 GB for the backup but only 177.07 GB are available. Select a larger backup disk or make the backup smaller by excluding files.
Latest successful backup: 22 March 2019

The backup disk needs 417.12 GB for the backup but only 179.62 GB are available. Select a larger backup disk or make the backup smaller by excluding files.
Latest successful backup: 22 March 2019

Is there something that is being left out so it won't delete the older backups?

Is there a manual way to delete older backups?

 

[chscag]

Is there a manual way to delete older backups?

Yes, but you have to do the deletions from within Time Machine. Do not try to delete backups any other way as that will destroy the continuity of the Time Machine backups. Just right click on a selected backup and then press delete. You will need to enter your Admin password first. Deleting backups has to be done one at a time and depending on the size of the backup can take considerable time to delete.

 

[a2jack]

New at time machine. So far, I find it works well, but is loaded with traps for newcomers.

Need a little help here: When you say " do the deletions from within Time Machine" what are the steps to get back in, to do this correctly ? Thanks a2

 

[chscag]

First, you need to enter Time Machine and of course have your Time Machine external drive attached. Then, to the right you should see all the Time Machine backups that were made by date. Just select a date and proceed as I described above. It does take a lot of time to delete Time Machine backups as they can only be deleted one at a time. And if the backups you made are large, it will be slow.