Time Machine back up and Music Storage

[SLFDMD]

Hi everyone. I had an account on here but can't remember the password or account so set up a new one. Anyways, quick question. I recently upgraded my iMac to an M1 and my external that I had set up kind of crapped at the same time. I bought a new external and have been able to do Time Machine Back Ups on it but I used to store my iTunes library on it as well and it won't let me add anything to it. I also backed up my laptop on it as well. Im pretty certain it has to do with the way I did (or did not) format it. Anyone have a rundown on how I can format it properly. Thanks in advance.

 

[SLFDMD]

So Basically I am looking for the correct format to have the following

1. Back up of Imac
2. Back up of Macbook
3. Itunes Music Library

I did the AFPS format first which I think it messing me up. I am now reformatting it to Fat32. Do I need have separate partitions for it? I can't remember if I did that with the previous back up. Thank you again.

 

[Dave Braine]

Split the external into three partitions, one for each of the above. Format for AFPS.

 

[MarkC426]

The only problem with this, is your music library is not backed-up.
Ideally you want an iTunes music disk and a backup disk.

For multiple backups, I think you would be better with Carbon Copy Clone or SuperDuper.
Time Machine works best if permanently connected to a machine for continued updates.

In an ideal world, separate drives:
TM disk for iMac
TM disk for MacBook
iTunes Media disk
Backup of iTunes Media