Constantly crashing OS on the bootable SSD

cerwik

macrumors newbie
Original poster
Sep 22, 2016
9
0
Hello,

I own the iMac (late 2012 - a thin model) on which my internal drive leaves. I still have OS installed on it, but I do not use it. As a temporary solution I had an external HDD connected via the usb from which I booted and I had no problem (except that it was slow).

As a replacement I bought the following:
- SSD Samsung 850 EVO 250GB
- RAIDSONIC ICY BOX IB-254U3 External Box

The SSD is therefore connected via USB and I have an OS installed on it and it boots me at startup. In the future, I'm planning to insert SSD into a mac, but I need to do it in a service.

Problem Description:
Occasionally (about once every 1-2 weeks) it happens that when the Mac is turned on, the OS boots from an internal crashing HDD. Also, sometimes when I wake it up from sleep (OS from SSD) it will stay stuck, I have to make a hard restart and then system automatically boot from an internal crashing HDD.
But the main problem is that SSD looks like it does not have any created OS and data partitions. Please see attachment - print screen from the Disk Utility (apple application), where it is seen that there is a partiiton without title and without data. I had a partition with a name and some data there. If I want to boot again from SSD, I have to install the OS again.
Disk Utility.png


Firstly I thought that I have bad SSD or an external box. I reclaim both of that and they give me new pieso from both. But now it happens again. So the SSD and the external box will probably be OK.

Then I thought it could cause TRIM on SSD. But I found it to be quite different and I use TRIM ENABLER.

It is possible that the internal HDD is causing the problem. I can temporarily format it without OS (I have not tried it yet). However, when I used to boot an external HDD, there was no problem. Only when I use the SSD in an external speaker.

Please write me your opinion what I make to do? Thank you.
 

Fishrrman

macrumors P6
Feb 20, 2009
17,160
5,520
Have you tried a different USB cable between the Mac and the SSD?

Did you set the SSD to be the boot drive in the Startup Disk preference pane?
 

cerwik

macrumors newbie
Original poster
Sep 22, 2016
9
0
Have you tried a different USB cable between the Mac and the SSD?

Did you set the SSD to be the boot drive in the Startup Disk preference pane?
Yes, I try some another cables between mac and ssd enclosure. And Yes, SSD is startup disk.

But I have a idea, where could be problem. SSD External enclosure is without power suply cable. SSD is powered by usb cable from imac. It could be problem when imac wake up from sleep mode. After wake up, Image remaine stuck (not always as I wrote). I have to make turn off imac with button. Maybe enclosure with power supply solve my problem.

But on the other hand, I have problem also, when I start iMac without wake up - start from turn off mode. :/
 

Fishrrman

macrumors P6
Feb 20, 2009
17,160
5,520
"But I have a idea, where could be problem. SSD External enclosure is without power suply cable. SSD is powered by usb cable from imac. It could be problem when imac wake up from sleep mode."

Something to try:
Go to Energy Saver preference pane and UNCHECK option to "put hard disks to sleep when possible".

Something else:
You could try turning off sleep entirely (except for "display sleep").
SSD's don't use much energy, anyway.
 

cerwik

macrumors newbie
Original poster
Sep 22, 2016
9
0
Thanks, it's good advise.

It really looks that best for me will change crashing HDD for SSD in service. I'm only affraid, that I will have the same problem then.
But now I think that problem is with crashing HDD still connected in iMac or external box. Or both.
 

nambuccaheadsau

macrumors 68000
Oct 19, 2007
1,739
409
Nambucca Heads Australia
With your Samsung SSD a USAP (USB Attached SCSI Protocol) is required according to some threads. These enclosures are up to 70% faster than USB SSD's when used as an external hard drive. Something to do with the 6Gb/ps not working well externally when not connected via SATA. Have a read of this link and as your iMac is a 2012 model, it comes with USB3 so that will be great.


https://www.startech.com/au/HDD/Encl...ort~S2510BMU33
 

cerwik

macrumors newbie
Original poster
Sep 22, 2016
9
0
With your Samsung SSD a USAP (USB Attached SCSI Protocol) is required according to some threads. These enclosures are up to 70% faster than USB SSD's when used as an external hard drive. Something to do with the 6Gb/ps not working well externally when not connected via SATA. Have a read of this link and as your iMac is a 2012 model, it comes with USB3 so that will be great.


https://www.startech.com/au/HDD/Encl...ort~S2510BMU33
Thanks for hint. But this "only" raise a speed - not solving my problem with boot OS and delete partition. Or not? :)
Otherwise put SSD into iMac will be better solution if I will get full speed.