I’m having a problem with a new M1 MacBook Pro for which, so far, Apple has told me they don’t have a solution. It would be great to know if others are experiencing this problem so we can provide additional feedback to Apple.
I have two Thunderbolt 3 external SSDs manufactured by OtherWorldComputing. Each of the external SSDs works fine when it is the only external device connected to the MacBook Pro. However, when both devices are connected simultaneously only one device receives power and is recognized by the MacBook Pro. I’ve called OtherWorldComputing and they could not suggest a solution. I called AppleCare support and they claim that they have received multiple similar reports and it seems to be a limitation of the new M1 hardware. I was told that it is possible to use two external SSDs simultaneously on the older Intel MacBooks. Currently, Apple does not have a solution to the problem and they could not suggest a workaround. I asked if purchasing a separately powered dock might solve the problem but Apple could not confirm that is a workaround.
Adam Engst told me that he has a new M1 MacBook Air and he has not seen the problem when he connects two external SSDs via USB-C, not Thunderbolt 3. So, the problem may be with external SSDs connected via Thunderbolt 3 but not via USB-C.
It would be great to know if anyone else is experiencing this problem or if they have the equipment can test and let us know their results.