Imac will no longer boot from external ssd

[bizon1]

I have been booting my 2011 27 inch imac from an external lacie ssd for about 5 months now with no problems. But now my imac will no longer boot from it. The only thing I did was shut down the imac and when I went to start up again I just keep getting the spinning wheel.


I hardly ever turn my imac off, I usually just put it to sleep. But we had a bad storm, so I figured I'd turn it off because one time the electricity went off while it was asleep and when I went to turn it on, this same thing happened. I was able to get it to boot up from the ssd again by booting from the internal hdd and then I unmounted the ssd and remounted it and then I could boot from it again.

I tried that this time and it would not work. I tried to boot my husband's macbook pro from it and it does the same thing the imac does, just keeps the spinning wheel.

It will spin for a few seconds, go away, the screen will get a little brighter, then the spinning wheel comes back, over and over.

If anyone has experienced this before or knows what to do, please help.

I did verify and repair permissions and verified disc, but it said it was ok.

Thanks

Oh, I'm running version 10.8 if you want to know.

 

[Nuke61]

I have been booting my 2011 27 inch imac from an external lacie ssd for about 5 months now with no problems. But now my imac will no longer boot from it. The only thing I did was shut down the imac and when I went to start up again I just keep getting the spinning wheel.

I'd try a Safe boot first. While booting hold down the Shift key -- this boot prevents any non-essential items from starting, starting only those things that are essential.

 

[bizon1]

Do I perform the safe boot while the external ssd is still chosen as the startup disc? Right now I have the internal hdd selected as startup.

Sorry if that's a stupid question, I just want to make sure I do everything correctly and I don't have much experience with all of this.

Thank you

 

[bizon1]

Ok, it does boot up in safe mode from the external ssd. So what does that mean?
And what do I do now? Sorry for my ignorance on this.

 

[bizon1]

Well, just wanted to give an update. I restarted the imac after I booted into safe mode and it started just fine from the external ssd. I still don't know what went wrong or what booting into safe mode actually did, but I'm glad it worked.

My concern now is if this will happen again. Like I said in my first post, this is the second time it has happened, although the fix was easier last time. Should I be worried? Is this a sign something is wrong with my ssd?

 

[Nuke61]

Well, just wanted to give an update. I restarted the imac after I booted into safe mode and it started just fine from the external ssd. I still don't know what went wrong or what booting into safe mode actually did, but I'm glad it worked.

Safe mode bypasses anything that isn't essential; my guess is that one of the caches that handles the extra stuff (beyond Safe boot) got corrupted, which is why Safe mode worked.

As for what you do now: After booting into Safe mode, you should be able to shut down and then reboot normally with the SSD.

Since this happened right after a lightning storm, I suspect that it's the cause, so you should be O.K.... BUT you have at least 1 backup, right?

One thing to be aware of is that you should really try to keep the space used on the SSD to <80% full. This was true of hard drives too, but this advice seems to have been lost with the advent of SSDs.

 

[Fishrrman]

[[ Well, just wanted to give an update. I restarted the imac after I booted into safe mode and it started just fine from the external ssd. I still don't know what went wrong or what booting into safe mode actually did, but I'm glad it worked. ]]

If it keeps working ok, I wouldn't worry about it, at least as long as you're properly backed up.

Since you have an iMac and are booting externally, I would suggest that you use either CarbonCopyCloner or SuperDuper to create a bootable backup (of the SSD) on the _internal_ drive in the iMac.

If you do this, you will have TWO "boot sources", so you won't have to worry about "no-boots" again. If you get a problem with the SSD, you can just "switch boot" to the internal drive, be up-and-running, and then "go to work" on the SSD to get the problems worked out.

Doing all this is very VERY easy -- even I could do it. You can, too.

 

[antman2x2]

Do I perform the safe boot while the external ssd is still chosen as the startup disc? Right now I have the internal hdd selected as startup.

Sorry if that's a stupid question, I just want to make sure I do everything correctly and I don't have much experience with all of this.

Thank you

Im using the LaCie SSD as a boot drive as well. I rarely ever completely turn off my computer but ive noticed a few times, during the rare occasion where I do turn off my computer, when I turn it back on it will sometimes miss the LaCie drive and I have to restart.

I guess there isnt much we can do, its a small problem.

 

[bizon1]

Thanks for letting me know that, it makes me feel better to know this happens to others as well.