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Level 1

11 points

after upgrading to Yosemite iMac reboots random reboots randomly

After upgrading from Mavericks to Yosemite, my mid-2011, 21.5 inch iMac (1tb HD, 8 gb memory) is plagued with random reboots. There are never any error messages - reboots seem more frequent when my Time Machine external drive is attached. I thought I had solved the problem after reading an article about Chrome browser (which I'd been using) using an inordinate amount of memory & CPU resources, so I switched from using Chrome to Safari. Switching to Safari seemed to resolve the issue yesterday, but today my computer is back to random reboots although it doesn't seem as frequent using Safari (only 3 reboots so far today),

I booted the iMac into Safe Mode & worked for several hours including making a Time Machine backup without any reboots. I've also run a hardware & hard drive check which showed no problems.

So, I'm at a loss -- if I use Safari & keep my Time Machine backup unplugged it seems I can work with only 3 or 4 reboots & hope they don't occur in the middle of some transfer or other work -- at the end of the day when I am finished working, I can attach my external drive & hope the backup completes before a reboots occurs. Very frustrating.

Any suggestions?

Thanks.

iMac (21.5-inch Mid 2011), OS X Yosemite (10.10), 1tb HD - 8 gb memory

Posted on Nov 7, 2014 3:13 PM

23 replies

mpalx2 Author

Level 1

11 points

Nov 18, 2014 9:46 AM in response to Linc Davis

After running the command in Terminal:

iMac:~ mpallett$ syslog -k Sender kernel -k Message CSeq 'n Cause: -' | tail | awk '/:/{$4=""; print}'

Nov 13 07:51:37 kernel[0] <Notice>: Previous shutdown cause: -128

iMac:~ mpallett$

Linc Davis

Level 10

209,547 points

Nov 18, 2014 9:54 AM in response to mpalx2

A negative shutdown code, if it happens repeatedly, may indicate a hardware problem. The precise meaning of the codes is not publicly documented.

Make a "Genius" a ppointment at an Apple Store, or go to another authorized service provider. You may have to leave the machine there for several days.

Back up all data on the internal drive(s) before you hand over your computer to anyone. There are ways to back up a computer that isn't fully functional—ask if you need guidance.

If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you have at least two complete, independent backups, and you know how to restore to an empty drive from any of them.) Don’t erase the recovery partition, if present.

Keeping your confidential data secure during hardware repair

Apple also recommends that you deauthorize a device in the iTunes Store before having it serviced.

*An SSD doesn't need to be zeroed.

mpalx2 Author

Level 1

11 points

Nov 18, 2014 10:03 AM in response to Linc Davis

I'll make an appointment soon. Thank you for your assistance with this issue!

fobin

Level 1

4 points

Nov 22, 2014 1:11 PM in response to Linc Davis

I came by accident to this thread. I was googling for a shutdown issues. I've got two Macs that have similar problems. Brand new Mac Mini is doing once a day. I run the syslog command and I get:

Nov 19 14:35:05 kernel[0] <Notice>: Previous shutdown cause: -128

Nov 19 19:55:37 kernel[0] <Notice>: Previous shutdown cause: -128

Nov 20 06:35:40 kernel[0] <Notice>: Previous shutdown cause: -128

Nov 20 10:58:17 kernel[0] <Notice>: Previous shutdown cause: -128

Nov 21 02:36:41 kernel[0] <Notice>: Previous shutdown cause: -128

Nov 22 07:54:30 kernel[0] <Notice>: Previous shutdown cause: -128

Now also my Macbook Pro which was in my lap just booted. I run the same command and got. This is mid 2012 machine.

Nov 22 22:51:54 kernel[0] <Notice>: Previous shutdown cause: -128

I've also heard sometimes when my Macbook Pro is in my backpack that it has booted by itself but I haven't then checked the logs.

As I said, Mini is brand new. It might have some kind of hardware failure. But now also Macbook Pro? This started with Macbook Pro when Yosemite was installed. Mac Mini has had only Yosemite since it's new.

And from the logs there never is any crash logs which seems odd.

soltltym

Level 1

13 points

Nov 25, 2014 4:57 PM in response to Linc Davis

This is complete B.S.!!! I have NEVER had to do any of this junk upgrading any previous version of OS X. There is something WRONG with Yosemite that all this wasted time is not going to fix. I have spent hours/days troubleshooting, reinstalling, monitoring, reading all reports, etc. and none of it has stopped the random reboots. Just because it worked for you, for a while, doesn't mean it is fixed permanently. Just wait. It will happen again.

mpalx2 Author

Level 1

11 points

Mar 3, 2015 9:16 AM in response to mpalx2

to followup on my original posting (for anyone who might come across it with a similar issue), I wanted to write that I did solve my particular random rebooting issue. Link Davis was correct in theorizing that it may be a hardware issue based on the results of a system test he suggested I run. Since my iMac was out-of-warranty & I didn't want to take it to the Apple Store unless I had to, I began to do what trial & error testing I could on my own.

One was to remove the additional 4gb of OWC memory sticks (2 X 2gb) that I'd installed a couple of years ago. Upon removal, my iMac immediately stopped randomly and spontaneously rebooting. It has now been almost 30 days & I've not experienced the rebooting issue that had become so frustrating - so I'm reasonably confident that the issue is resolved for me.

I don't want to fault the OWC memory directly - I think they sell a fine product as I've used OWC memory in other Macs without issue. Plus, the memory sticks I removed worked fine in this same iMac under Mountain Lion and Mavericks. It seems there is something about the way Yosemite uses memory that caused my iMac not to like processing information through memory from different manufacturers - resulting in periodic rebooting.

Again, I post this information in hopes it may help someone with a similar issue. The continual rebooting was incredibly frustrating; so much so I almost entertained a return to Windows computing -- almost.

soltltym

Level 1

13 points

Mar 3, 2015 10:38 AM in response to mpalx2

It is encouraging to know someone has the same conclusion in regards to the random reboots and logins. I had the exact same experience, only mine was Corsair Value Select memory modules. Once I removed them all was well, but after a while I got brave and added the same memory back into my iMac. I thought it was ok, but after a couple of days, the reboots came back.

I am totally convinced this was the cause of my problems from the beginning, and had nothing to do with OS X Yosemite. What was so frustrating was the fact that I ran lots of hardware tests and at no time did it indicate anything was wrong with the memory. That tells me these tests are just not very dependable. Memory is touchy, and random, but once the OS needs a particular address, and that address is in a bad place, thar she blows!

jack634

Level 1

8 points

Jun 4, 2015 5:15 PM in response to soltltym

As I have a similar issue and am using Crucial memory sticks, what memory type/maker are you using to resolve this issue?

after upgrading to Yosemite iMac reboots random reboots randomly