Cannot Do A Safe Boot In Mavericks

I have the same problem with my 27" Late 2012 iMac with a 3TB Fusion drive. The difference is I have not yet upgraded it to Mavericks. I am still in Mountain Lion. I do no think this issue is a Mavericks issue or at least not limited to Mavericks machines.

Jay

- It starts with the progress bar on the bottom (at which time I let go of the Shift key),

- The progress bar gets to about 1/3 the distance then disappears,

- The screen goes blank and then my iMac restarts itself and ends up as a normal boot.

I'm experiencing EXACTLY the same problem. Macbook Pro with Retina Display, Mid 2012.

Linc Davis has stated in a number of his posts that:

Linc Davis

...
Note: If FileVault is enabled on some models, or if a firmware password is set, or if the boot volume is a software RAID, you can’t do this. [i.e. Boot into Safe Mode] Ask for further instructions.
...

Could that be the issue here?

same problem here, new iMac with Fusion drive and mavericks, I tried zapping pram, disconnection all peripherals, erased hard drive and installed virgin Mavericks, still cannot boot into safe mode.
I can when I boot off an external drive with Mavericks.
I have contacted support and done the feedback. Support will get back to me.

no filevault or firmware password.

not sure about the OS, I will try erasing and installing lion

I have this same problem with my late 2012 27" iMac with 3TB fusion drive. Reinstalled Mountain Lion - and safe boot works. Did a clean install of Mavericks - and it will not safe boot. I brought it in to the Apple store tonight - and they did not have a solution. They happened to have a brand new 2013 27" iMac with 3TB fusion drive - and it would not safe boot either. However, a 2013 27" iMac with 1TB fusion drive - did in-fact safeboot. The apple store has escalated this issue with Apple. I am sure they will come up with a resolution soon. I will post back when I hear something.

So last night I erased my fusion drive and installed Mt. Lion and lo and behold it was able to boot into safe mode, reinstalled Mavericks and again was unable to safe boot. I will speak to Apple Support today, stay tuned...

This may be from a faulty drive formatting issue, that can result in a hang or reboot of the system when loading in Safe Mode: http://reviews.cnet.com/8301-13727_7-57573680-263/what-to-do-when-a-mac-wont-boo t-to-safe-mode/

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My iMac (late 2012) with 1TB Fusion drive will not boot into Safe Mode under either Mountain Lion or Mavericks. I tried the Terminal commands referenced above to setup a Safe Boot, and that turned into a bigger problem. It would start a Safe Boot but couldn't complete it, and then just started the cycle again - an endless loop. The 'back-it-out' instruction had to be modified to reboot normally.

Executive Summary:

Some iMac models can not Safe Boot

I found that in order to see the message that I had booted in safe mode I had to turn automatic login off, it was at the login screen that the red "safe boot" appeared in the upper right hand corner.

This is as an aside, I am still only able to safe boot to mountain lion and not to mavericks.

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I am having the same issue. I have an iMac 27" with a 3TB Fusion Drive from early 2013,

Exactly the same problem here.

imac 27"

1tb fusiondrive

mavericks

cannot boot into safe mode, it just reboots 1/4 through the progress bar when trying to safe boot

Exat the same here to:

A gray progressbar, then a restart into normal mode:

iMac:

27" late 2012

3,4 ghz i7

8gb ram

1tb fusion drive

mavericks

my macbook also shows the progressbar, but it enters safe mode after the completion.