Cannot Do A Safe Boot In Mavericks

- 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.

..

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.

MacMini

late 2012

1To fusion drive

16 Go Ram

mavericks

No way to start in safe mode

MacBookAir 11inches

mid 2011

SSD 256

4 Go RAM

mavricks

Succeed in starting in safe mode

If I did try the safe mode, it's because I am experiencing trouble with my MacMini...

Sleep leads to Shutdown itself.

I am obliged to remove the power cord to be able to restart... Reset SMC done several times....