My S352BU33RER is connected directly to a USB-A port on a Mac Studio M2 Max running macOS 26.6.2. After powering the enclosure off and back on, it appears as “JMS56x” in the USB device tree in System Information, but the drives do not appear in Disk Utility.
This also happens in Standard mode, with the two drives presented individually. I have already tried a different USB port and a different USB 3 cable. The enclosure works correctly on Windows, and the problem disappears when using a USB 2 cable on the Mac.
Is there a firmware update or a workaround to resolve this USB 3/UASP issue on macOS?
Thank you for asking your question here on the the StarTech.com Community.
We are sorry to hear about the strange issue with the drives installed in the S352BU33RER not reconnecting after powering it off and on again. The USB 2.0 cable connection working is interesting clue.
I was able to confirm, after checking all of our product information for the S352BU33RER, that there are no firmware updates available for this dual bay enclosure. However, we can certainly look into other ways to help.
Here are a few suggestions to try.
When the drives are not recognized, is there any change when also disconnecting or reconnecting the USB connection for the S352BU33RER while it is powered on?
Try connecting the S352BU33RER to the Mac Studio M2 Max via a USB-C connection, either with an adapter or a USB-C to USB 3.0 B cable.
Try connecting the S352BU33RER using a USB 3.0 or better hub, dock, or other similar device. Often a direct USB connection is best but occasionally adding an intermediate device can help.
Confirm that the S352BU33RER continues to work fine with other computers. If available, test with another model of computer to help isolate what is happening.
These recommendations could help get you up and running, or further narrow down what is happening, if you have not already tried them.
You are welcome to reply here again with your results if you would like us to look into this further with you.