Re-initializing Time Machine

[SteveSawyer]

On my old system the TM volume was pretty consistently only half full. The new machine has less space than the old one (1.5 vs 2 TB), but I attached a fairly full 1TB SSD, and before I got around to erase this drive and tell TM to ignore it, it dutifully backed it up and now my TM volume is 90% full.

I’d like to just have TM start over but unsure how to proceed with that.

 

[Rod]

If you are happy to just start over with your TM backup launch Disk Utility which is in Applications > Utilities folder or just type it into Spotlight.
There you will see something like this;



Choose the Time Machine drive in Externals (circled) and click on Erase in the top row of tabs. You can choose a name for it at this point as with mine, Time Machine2.
When you open TM Settings choose the external drive you just erased to replace the old TM backup and ensure you exclude anything you dont want backed up.
This will result in a new TM backup of just your internal drive starting from that time and date.

 

[SteveSawyer]

Yeah, I'm fine just starting over . This is a new machine so it only has a couple weeks worth of backups. So doing this on the drive that TM is currently using won't be a problem?

 

[Rod]

No, I do this every year, roughly a month after upgrading to the next macOS. I use a HDD (spinner) type External HD, same one for 5 years now.

 

[SteveSawyer]

No, I do this every year, roughly a month after upgrading to the next macOS. I use a HDD (spinner) type External HD, same one for 5 years now.

Ok!! Thanks, Rod.

 

[SteveSawyer]

For anyone coming across this thread in the future, note that there is an important step missing from the above. Once the drive is erased TM has to be told to "forget" the drive and re-establish it as the target for TM backups.

Time Machine isn't recognizing backup drive