sudo disable trimforce doesn't work Since upgrading to High Sierra my boot time slowed down considerably (from ~10 seconds to 90 seconds). Googling this problem suggests disabling Trim might work as a solution, which you do via the sudo trimforce disable command, but it doesn't actually seem to disable Trim.

After running sudo trimforce disable and pressing y twice, my Mac automatically reboots but after rebooting, system_profiler SPSerialATADataType | grep 'TRIM' or System Information-&gt;SATA/SATA Express still shows TRIM Support: Yes

I also tried to disable System Integrity Protection before disabling Trim, and that doesn't seem to work either.

Anyone got any ideas?
Other users have also reported the same issue. TRIM may not actually be disabled on macOS even if forced. In my testing on a 3rd-party SSD, I could never disable TRIM on High Sierra.

On another note, it might be possible to improve your boot performance by following a guide I posted back when I was having similar issues.

The gist of it is that re-blessing the boot partition, and resetting SMC+NVRAM may improve boot performance. To re-bless, simply go to System Preferences > Startup Disk, select the desired boot partition, and restart from there.