> Upgrading from Thunderbolt 2 to 3
My Mac mini 2014 has several external disks for Time Machine and other storage. When my M1 Mac mini arrives, will they work with it?
In general, M1 Macs should work with all existing disks as long as they can be connected to its Thunderbolt 3/4 or USB ports. There are some catches when upgrading from older models, though.
Your old Mac mini has two Thunderbolt 2 ports, but the M1 version has USB–C sockets for Thunderbolt 3/4. External disks with their own power supplies work fine with Apple’s Thunderbolt 3 to 2/1 adapter, but that can’t supply power to compact drives which draw instead from the Thunderbolt cable: those need to be connected to a powered dock to work. Where you can change their enclosure to USB 3.2 type with a USB–C connector that could be a good solution. If you haven’t upgraded to Big Sur, you’ll also need a disk that can be formatted in APFS and has sufficient free space for your Time Machine backups. If you can, archive your existing backups in safe storage so you can return to them as necessary, and start your M1 off with a fresh backup disk.
You can start up M1 Macs from external disks, but as of macOS 11.1 these can prove tricky to get working. Most reliable are Thunderbolt 3 SSDs, which are also the most expensive. Plain USB 3.x SSDs connected to a USB–C port may work fine, or may fail to boot. That should be fixed soon.
CAN I USE AN OLD iMAC AS A MACBOOK PRO DISPLAY?
Few iMac models support Target Display Mode. These include 27–inch Late 2009 and Mid 2010 models, and Thunderbolt iMacs from Mid 2011–14. No more recent models, including those with Retina 5K displays, support this feature. See bit.ly/ mac362imdsply.
WHICH PRINTERS ARE SUPPORTED BY BIG SUR?
As with Catalina and other recent macOS, Big Sur supports all printers with AirPrint, as listed at bit.ly/ mac362airprint. Apple still provides some legacy drivers for older printers without AirPrint, see bit.ly/ mac362printdrvrs. The latest version 5.1 of those drivers for HP printers is at bit.ly/ mac362hpdrvrs.