Not sure if the enclosure I got was defective or there is a 'handshake' problem with M1 Macbook Air. Using a fanxiang S690Q 1TB NVMe in this enclosure, I was able to connect with my M4 Mac Mini, but not my M1 MacBook Air. Used the same cable so not a cable issue. I like UGreen products so ordered another UGreen 40GB/s enclosure (ASIN# B0D3WT2T8C) that lists M1 compatibility in description and it works fine, with the stated speeds. There is another review that questioned M1 compatibility so likely this could affect others.