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->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?

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    I am leery that disabling TRIM will increase performance. TRIM is only a subset of AT commands used by the drive to mark deleted blocks as such and return either random data or zeros when a read request is sent. Before embarking on this, I would try starting with a fresh install (wipe the drive, then install clean). As always, make a full backup before proceeding. – Allan Jul 23 '18 at 12:46

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.

  • If you find an error in a post, please correct it by editing it instead of pointing it out. Also, link-only answers should be avoided as they will become useless if the linked page goes down. Please summarize the relevant content directly into your answer instead. – nohillside Jul 23 '18 at 9:56
  • @nohillside Thank you for the pointers. Will keep this in mind for future posts. I have a question though - If I come across a question asking - is this command correct/what's the correct command...? - then would it be appropriate to edit the command in the question itself or should it be a separate answer (as I had done here)? Sounds like in such a case the latter might be better. – mayankk2308 Jul 23 '18 at 10:59
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    Of course, in such situations an answer is the right way to go :-) – nohillside Jul 23 '18 at 11:48
  • Unfortunately following your guide didn't work for me. When booting up my Apple icon actually shows up pretty quickly, but the slow part of the boot is after I input my password to my username, where it gets stuck on the progress bar at about 70-75%% for about 1 minute before the boot finishes. – Monado Jul 23 '18 at 22:52
  • @Monado Reset SMC again in this stage. Could resolve it. – mayankk2308 Jul 24 '18 at 7:55

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