My 2TB external drive keeps disappearing every time I boot my Mac I have an external LaCie Porsche 9223 2TB drive connected to my Macbook Pro 15 (2015) via USB3. After I converted it to APFS after upgrading to macOS High Sierra, it keeps disappearing randomly from Finder/Disk Utility and the "/Volumes" folder, and nearly every time I boot my Mac.

This is what puzzles me though:

If I clean/remove the Dyld shared cache via Onyx, the drive shows up momentarily on the desktop/Finder sidebar with (seemingly) no problems whatsoever. Disk Utility reports that the disk is OK. The next time I reboot: poof, gone .

Does anyone have a clue what's going on?
And why the "dyld shared cache" cleanup is like a magician's reappearing trick every single time? If I only knew why that works, I would probably/most likely find a way to prevent it from happening again.

Best regards,

Andreas



Macbook Pro (2015), macOS High Sierra 10.13.2, 16gb RAM, 500gb SSD
After upgrading to High Sierra, I had the same issue with my LaCie shared not listed in shared devices, coupled with SMB hanging without connecting to remote servers.

The SMB issue was solved by changing the SMB version to v2 in the /etc/nsmb.conf configuration file and rebooting the Mac as recommended in this post on SMB share deadlock. After the reboot with the new /etc/nsmb.conf, shared devices were again correctly listed in the sidebar including my LaCie shared disk, so I surmise both issues are linked.

The /etc/nsmb.conf file I use is:

$ cat /etc/nsmb.conf
streams=yes
soft=yes
signing_required=no
protocol_vers_map=2
file_ids_off=yes