"Suitable" external drive for macbook air?

AAhrens wrote:

Thanks, but how do I format it? I thought I had already done this when I first connected it last year.

You use Disk Utility to format an drive.

Erase and reformat a storage device in Disk Utility on Mac - Apple Support

AAhrens wrote:

What external hard drives can I use for a "suitable" external drive? I've had a Seagate One Touch for a while, and just realized that while it's performing regular back ups in Time Machine, the folders are all empty.

When I went back into Time Machine settings, and selected the One Touch, it said I needed to connect to a suitable external drive. This one was recommended for my Macbook Air when I bought it last year, but now Seagate's website says these "older" drives need to be reformatted to work on macbooks' newer systems. (Seagate's chat function is not functional, so I can't get help there.)

Any drive you get should be formatted for use on your Mac upon first connection to the computer. Any SSD would be suitable and should work. If you'll be using it for Time Machine backups it should be 2 - 3 times larger than your internal drive.