Can't format external drive to Mac OS Extended-format

[dewjack]

I want to dedicate an external drive for time machine. The drive, a Seagate, 5TB HDD was initially formatted as Windows NT, I then tried to re-format it into Mac OS Extended, which didn't work. I then formatted it into APFS using High Sierra on my MacBookpro, then reconnected it to my Mac Mini, but it still does not work, so it won't accept the hard drive for time machine. I have a mac mini late 2012, 2,6 GHz Intel Core i7. Running on Sierra 10.12.6.

My final aim is to upgrade to High Sierra, and therefore wishes a backup first.

 

[hwojtek]

GUID or MBR?

 

[chabig]

Be sure to select GUID as the partition map, then it should format to HFS+. If that fails, start with the Partition tab and make sure to choose one single partition for the entire drive.

 

[Fishrrman]

Here's something else to try:
1. use disk utility to format it to exFAT. Yes, that's a PC format, but do this anyway, in order.
2. now use disk utility to format (the exFAT drive) to "Mac OS extended with journaling enabled, GUID partition format".

Does this work?
(It did for me once or twice when a drive didn't want to reformat/erase to Mac format.)

 

[dewjack]

Really thanks.
It didn't accept to format it to exFAT either, but I tried it on a third computer, with el Capitan, it worked immediately, straight to Mac Os Extended, strange.