I've migrated from an old iMac to a new one. I keep getting messages that there isn't enough room on the TM hard drive to perform a back-up. I THOUGHT it would just write over the oldest files, like it use to do. But it won't.
I want to Erase this current 4 TB HD but I keep getting a message that it can't be done because the Finder is using it.
I've tried everything that I can think of ...
iMac 27" 5K, 10.14
Open disk Utility and erase that drive
NOW, after spending a good half hour this early afternoon trying to Erase it ... it suddenly worked?
As I said, I had tried all of those suggestions before, but kept getting a message that I could neither Erase or Unmount it because Finder was using it ... although I had stopped the attempts at backing up the day before.
Yup, those are all of the obvious solutions ... I'm asking here because none of them work.
There is something else going on here. Perhaps I need to also plug that HD back into my old iMac and do the same things from that computer?
Turned it off but did not disconnect from the iMac. Do you mean disconnect and the reconnect? ... in order to Erase and re-use?
Did you remove the disk and turn off Time Machine?
No, I meant in System Preferences > Time Machine, click Select Disk…, choose the drive and click "Remove Disk".
How can one Erase the Time Machine external Hard Drive?
