If Rita is using the external for Time Machine, she cannot use APFS. TM drives MUST be formatted Mac OS Extended (journaled). I believe, however, that if she sets up TM, the drive will automatically be formatted correctly. As I understand it, TM drives can be formatted APFS in Big Sur.


Jon

macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365