External hard drive

Welcome to Apple Support Community.

I like LaCie drives.

For a regular, external USB disk, see these options sold by Apple:

• LaCie Mobile Drive 4TB External Hard Drive USB-C - Apple
• LaCie 4TB Rugged USB-C Portable Hard Drive - Apple

For a USB external SSD (faster than a hard drive), see the: LaCie 500GB Mobile SSD Secure USB-C Drive - Gray - Apple.

If you have an iMac (Late 2015) or earlier, you will also need this cable. 

Jack

joan67 wrote:

Hi thx do they automatically back up when turning on the computer

If you Back up your Mac with Time Machine - Apple Support, then your Mac will be backed up to the external HD automatically, around every hour.

Jack

Of course they work on Monterey. I've got two that work without issue on Monterey. Every maker produces a lemon every now and then and Seagate has had it problems. But one person's experience doesn't mean the whole world has the same experience.

I use Samsung and WD drives mostly SSD's.

The technology is mature; pretty much any well known brand will work just fine.