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In another thread I mentioned that my MBP was unable to restart after I updated from 10.10.5 to 10.10.1. I had to go to the recovery partition and reinstall OS X. After that everything worked fine for a few days.

This morning I was trying to find out if Trim was still enabled, but couldn't find a way to get a report on it's status, so I used the Trimforce command to enable it. The system reported that the enable was successful and that the system would have to restart. But again, it failed to start up. I get the Mac logo, but the progress bar remained completely empty for over an hour.

I went again to the recovery partition to run a check on the disk, and that reported the disk is OK, but still the system would not restart. I'm running the OS X reinstall again, and after that I'm probably going to have to back to Yosemite and hold off on updating other Macs until I find out why this is happening.

But, I'm wondering if there is some problem with Trim on the Samsung EVO under 10.11. It worked fine in Yosemite. Could Trim be stalling the startup process?

But, I'm wondering if there is some problem with Trim on the Samsung EVO under 10.11. It worked fine in Yosemite. Could Trim be stalling the startup process?

Not likely.

I am able to enable TRIM on SSDs connected via USB 2. On the first five iMacs where I have installed an SSD, I used a usb dock and did the following.

a) ran Time Machine to each of the backups (if more than one)
b) turned off Time Machine in System Preferences
c) download the 10.10.5 installer to your drive or copy a zipped version onto it (must be zipped if you downloaded from another Mac or it might not open due to permission issues).
d) formatted the SSD in Disk Utility
e) install Yosemite 10.10.5 and use Migration Assistant to pull everything off the old drive as part of the install.
f) made it the boot drive in System Preferences and rebooted – things can get weird if this step is not done.
g) ran sudo trimforce enable in Terminal.
h) re-enabled Time Machine and ran it – sometimes it updated the old backup; other times it created a new one.
i) after I had everything verified and working, I installed the SSD into the iMac.

That took too long. On the next five, I shortened the process. It looks like more steps but it takes less time

a) ran Time Machine to each of the backups (if more than one)
b) Turn Time Machine off
c) download the 10.10.5 installer to your drive or copy a zipped version onto it (must be zipped if you downloaded from another Mac or it might not open due to permission issues).
d) install the SSD
e) attach the original drive via a usb dock (must be usb as Intel Macs won't always boot from FireWire).
f) boot or option-booted into the original drive.
g) selected the original drive as the startup drive in System Preferences if you option-boot and restart. Again, you have to do this step or some things don't work.
h) format the SSD in Disk Utility
i) run the Yosemite installer onto your SSD and use Migration Assistant to pull everything over.
j) select your new drive as Start-up and reboot.
k) run sudo trimforce enable in Terminal
l) re-enable Time Machine and ran backups

Mine was a little different as I was already running the SSD via eSATA but not enough to make a difference.

When 10.11 came out, I updated only two of the Macs I maintain. When 10.11.1 was released, I updated the other eleven (others have not been updated to Yosemite for one reason or the other or have Apple SSDs OE). I did not have to re-enable TRIM in any of them. Checking About This Mac and drilling down to the drive, I got TRIM Support: Yes

These are generic pictures but I have and use both types. Because I was doing more than one, all of mine were in use simultaneously.

This type can be had with eSATA in addition to usb. FW and TB versions are also available. I ran my iMac from one of these for over a year before I installed one internally.


These are great since you can hook any type of drive except SCSI.


If you have a USB drive enclosure lying about, that works well as long as it is for SATA drives. I have a few of those, too.

mikehalloran wrote: I did not have to re-enable TRIM in any of them. Checking About This Mac and drilling down to the drive, I got TRIM Support: Yes

I had already followed your procedure more or less when I had Yosemite and move everything over from my old mechanical drive to the SSD using Time Machine and a universal USB drive connector. Similar to the one you show below by much simpler.

I looked at About This Mac, and saw the same thing. But having Trim Support does not mean that Trim is enabled, just that it can be enabled. At least that's what the MacUpdate article on the matter has to say. I can't find anything that will confirm that Trim is enabled and working. And when I execute the enable command the system tries to restart and fails. It's back to Yosemite for me.

But having Trim Support does not mean that Trim is enabled

Not correct. If you disable TRIM, that will change to TRIM Support: No

Run sudo trimforce disable and see for yourself.

mikehalloran wrote:

But having Trim Support does not mean that Trim is enabled

Not correct. If you disable TRIM, that will change to TRIM Support: No

Run sudo trimforce disable and see for yourself.

OK, thanks. The article I read said that this just tells you whether the Trim function will work on the drive. I'll take your word for it that they're wrong, and it will read No if I disable it. I'm not going to fool around with it. The last time I ran the Trimforce command, I had to reinstall OS X.

I'm trying to figure out how to go back to 10.10 without erasing the disk. From what I've read, I can't use Time Machine because it has been run since I updated to 10.11, and the System stuff is excluded from my Time Machine backups. I can't simply install 10.10, because the Mac will insist on keeping the most recent OS version. I can erase and reinstall everything, or partition the drive and install 10.10 on the newer partition. I can buy a new SSD and put a 10.10 version of my Mac on it. None of these options look that attractive.

That was the short answer. My wife was dragging me out the door so that I couldn't finish.

TRIM is a function of the Mac OS since 10.7. It is not a function of the drive. This is also true for Windows and LINUX. When you enable TRIM, you are allowing the OS to TRIM your SSDs. Disable it and it won't. That's why TRIM Support: Yes or No really does mean that it is or isn't enabled.

Before 10.10.4, Apple wasn't allowing TRIM to work on non-Apple drives. Therefore Cindori's app was great for 10.9.x – 10.10.3. Before Mavericks, a rather complicated set of Terminal commands could enable TRIM. I tried every set of commands that I found in 10.9 and none worked. Trim Enabler.app (eventually) worked. I paid the $10 shareware fee and found it money well spent – even though I stopped using it after 10.10.4.

Running sudo trimforce disable, checking the status, then running sudo trimforce enable doesn't hurt anything. It just takes some time. Some sudo commands are destructive but this pair isn't. If you want to check it or if you suspect that TRIM is your problem, disable it for awhile and see what happens – you cannot harm your system by doing so.

There are many reports of specific SSDs that do not like TRIM but they are all running LINUX. Search for specific models that have problems with TRIM in Mac or Windows – I can't find any.

Here's a pretty good article that I've read recently:
http://arstechnica.com/gadgets/2015/04/ ... rim-right/

Mike, thanks for the details. I expect my drive is not one of the few that doesn't work with Trim. It's a Samsung 850 EVO. About turning Trim on and off: when I turned it on, (or thought I was turning it on using Sudo Trimforce Enable), the system told me to Restart. So, I can just ignore that?

Running enable or disable always requires a restart. All you are doing is telling the OS that it's ok or not ok to run TRIM.

I'm running an 850 EVO 2T without a problem. My wife's 2011 now has an 850 EVO 500G. With two exceptions, the other iMacs have a 1T. So that makes nine.

You can reinstall Yosemite either on another partition or by erasing the SSD and pulling the files via Migration Assistant from the old drive or a Time Machine backup.

What about your old drive? Is it available via USB?

Let's go back to the problem. Have you reset the NV RAM? If not, do it. Then reset the SMC. It's a different procedure on a MBP then on an iMac. Ether of those can be the real problem. One of the iMacs I did had the same symptom now that I recall and resetting the SMC did the trick. I would also do a Safe Boot to reset the caches to default.

Reading your posts, my money is on the SMC. Read the link in the next post.

To reset the SMC on a MBP with removable battery:
Shut down the computer.
Disconnect the MagSafe power adapter from the computer if it's connected.
Remove the battery.
Press and hold the power button for five seconds.
Release the power button.
Reconnect the battery and MagSafe power adapter.
Press the power button to turn on the computer.

Reset SMC, MB without removable battery:
https://support.apple.com/en-us/HT201295

SMC reset: Desktop Mac (iMac, Mini, Mac Pro)
Quit all applications
Shut down completely
Disconnect all peripherals (optional but recommended)
Disconnect power cable for minimum 15 seconds
Reconnect power cable
Wait minimum 5 seconds, restart your Mac.

Reset NV RAM:
Shut down Mac completely
Hold down Command-Option-p-r keys.
Press Power
Listen for startup chimes
Release keys after startup chimes three times.

Safe Boot:
Shut down completely
Holding Shift Key, press Power
Release Shift when you see login screen (this may take a few minutes)
Login with Admin password
When Mac has fully booted, shut down completely
Restart.

I'm confused and ask for clarification. . .

Mike, if I am reading your posts correctly, you're able to use TRIM on SSDs housed in external USB-based enclosures of some kind. Yes? No?

I just enabled TRIM on my happy Mac Mini (noted in my signature) in hopes to use it on my two external SSDs. The Mac Mini has the original SSD that shipped with it so I know that it has been getting "trimmed". However, it seems that the TRIM function is not reaching the two external SSDs (housed in USB 3 enclosures) after I enabled TRIM via the Terminal. I run Disk Utility and there is no indication that TRIM took place.

Ted

Disk Utility can't tell you certain parameters of drives connected by USB or TB including SMART or TRIM.

If you run Repair Disk on a connected drive, it should indicate if it ran TRIM. Run it on the entire drive, not the mounted volume.

Go to About this Mac. Drill down to your connected drive. What does it say about TRIM Support! Yes or No?

A lot more info in this thread
http://www.motunation.com/forum/viewtop ... =4&t=59419

mikehalloran wrote:Disk Utility can't tell you certain parameters of drives connected by USB or TB including SMART or TRIM.

If you run Repair Disk on a connected drive, it should indicate if it ran TRIM. Run it on the entire drive, not the mounted volume.

Go to About this Mac. Drill down to your connected drive. What does it say about TRIM Support! Yes or No?

A lot more info in this thread
http://www.motunation.com/forum/viewtop ... =4&t=59419

Thank you, AGAIN, for your time and sharing of expertise!

I did use "Repair Disk" found within the Disk Utility program. Still, there is no indication that TRIM was or was not used.

After doing the digging that you suggested, it seems that the Mac Mini recognizes the two SSDs housed in USB 3-based enclosures NOT as SSDs. Also, it doesn't indicate if either of these two SSDs are TRIMable. Now, I'm more confused. Both external SSDs and enclosures were purchased (and manufactured) by OWC. Additionally, all are a couple of years old too. Especially with regards to the SSDs, there might be Firmware Updates that need to take place. . . ??? I don't know.

What matter most, and what is most important, is that both SSDs, and their external enclosures, function as intended. All are in good order. (What I haven't done, yet, is backed them both up. This needs to get done. Ugh!)

Again, thank you!

Ted

I never did get around to reverting to Yosemite, and won't until I've verified my backups. Meanwhile, this message has popped up now and then. Anyone seen this? Maybe it's the reason I can't restart without reinstalling El Cap. Google says it has something to do with SuperDuper, so it might be something that app is looking for, but Google also says it is a basic OS X file, it has to be there, and OSX must be reinstalled if it isn't. But I've installed 10.11 three times now, so that doesn't seem to be particularly effective.