Time machine old folders...

Should I move my documents (300 GB) elsewhere

Yes.

and then delete and reformat the external drive? If yes, how ? Thank you :-)

In Disk Utility,

Click the View popup menu button and select “Show all Devices”

Select the external drive device

Click Erase button.

Select a Format—really doesn’t matter, but APFS (case-sensitive) is what TM will use to reformat it.

If you want to partition it so you can store other data on the drive, use the Partition button instead of Erase. Make the first partition about twice the size of your data that you are going to backup. Then make the rest whatever format you want.

Partition a physical disk in Disk Utility on Mac - Apple Support

Some considerations.

• How are you backing up the 300 GB of data?
• Maybe just purchase another drive for TM that is the size you need (~2X data size). You could use it for temp transfer of 300GB so you can reformat old drive. Or, get a drive big enough to back up both drives. TM can also back up external drives.

I have another Toshiba 2TB drive that is new. I can move my documents (300 GB) there... but how do I move them from one external HD to another? I have only one USB port on my MacBook...

Without a hub, the only idea I have is to move them to the internal drive, then to the other external. Could be really slow if you don't have the space on the internal.

Neither of those requests are how Time Machine was designed. If that’s what you want, you should use a different backup program. I don’t know which ones would have those features.

The oldest backup would contain the original files from the full backup. Subsequent backups write hard links to unchanged files (no space used) or changed files. Each one is not a full set of files, so deleting a folder would not necessarily recover any space at all.

The way hard links work, you cannot tell them from the actual (original) file, and deleting a hard link doesn’t recover the storage until the last link is deleted. You can use the Time Machine interface on your current backup to remove individual items from the backup, but that wouldn’t be just the old versions—it would be all versions.

If you want to delete the old backups, erase the drive and start a new backup. If you want to restrict the size, create a partition or use a smaller drive. That might result in it not being able to back up if it cannot delete enough old backups. Then you’ll need to erase and start over.

If you decide to create a new backup, Time Machine will use the new APFS backup scheme. That will take full control of the volume you provide (you can’t use it for anything else), and it prevents deleting individual backup items.

I will concede to more learned Contributor @Barney-15E but using the one drive to more than one purpose , especially Time Machine Backup on Big Sur - may seem a good usage of available space but does complete the matter somewhat.

It is my understanding - Big Sur TM Backup utilities like to take total control of the Entire drive. Then there is the issue of All the Eggs in One Basket. External Drive do fail and if / or when that happens - the Eggs are all Scrambled.

As for manually removing backups from the drive - again IMHO is dangerous can can lead to a corrupted index that TM Backup relies upon to keep track of thing it has backed up.

bszorad wrote:

Okay I understand... I have another folder on the Toshiba HD with documents (about 300 GB)... So can I just delete the Backups.backupdb folder and start from scratch with a new backup?

You can theoretically delete the folder, but people have had trouble getting it to erase from Trash.

Then, when you tell Time Machine to create a new backup on that drive, it will format the drive APFS (case-sensitive) deleting the other data. I believe it cannot convert and will erase the drive, but I don’t know.

Or delete all folders in the Time machine and just keep the original folder from 10 October 2020?

I don’t know how it would react, but at best I think it would keep the current format of the drive, but it will complete a full backup, so you’d use up twice the space required. At worst it would see the corrupt backup and start over formatting the drive APFS.