MacMini 2018. 2 Acacias 405 NVMe SSD Enclosures with 2TB Lexar NVME strips APFS formatted, Sonoma installed, connected to USB4/Thunderbolt ports.
Expected behavior: during startup with option key pressed, choice between internal HD or either external NVMe SSD Enclosures.
What happens: no startup choice, automatic startup of last time chosen HD.
Second NVMe SSD Enclosure invisible.
Mac mini, macOS 14.3
How did you get Sonoma installed on the external drive? Using this Mac or another one?
No matter what you should see the Option Boot screen with the Apple boot picker menu. Make sure to hold the Option key immediately after hearing the startup chime. Holding it too soon can sometimes prevent the system from recognizing it....same with pressing it too late....you really only have less than a second to press it after the startup chime.
Disconnect all external devices from the laptop to make sure you can get to the Option Boot screen. Then connect the external Sonoma boot drive to see if it appears as a boot option.
Does the external drive appear as a boot option if you go into the Startup Disk System Settings? Can you even see & navigate the external Sonoma SSD?
Just to confirm you have the plain TBU405 enclosure and not the TBU405Air version since the "Air" version only works with Thunderbolt 3/4 & USB 4....the "Air" version is not backwards compatible with USB3.x.
Please see screenshots. Clearly Thunderbolt 3 drives with NVME strips.
After the Startup Manager shows the first drive and the internal drive, the second one remains invisible.
Did a SMC reset, to no avail.
No, not 2 Sonoma installs on one drive. 2 Acacias 405 NVMe SSD Enclosures with each a 2TB Lexar NVME strip.
DriveDx reports excellent health of both internal Apple HD and Acasis drives
Good catch, for some reason I thought it only had two USB-C ports.
MacMini 2018 (4 port USB/Thunderbolt) does not function correctly with 2 NVMe SSD Enclosures
