I purchased Lion from the Mac App Store and installed it on my mid-2009-era MacBook Pro. The installation went smoothly and the computer restarted itself on schedule. I heard the startup noise, saw the Apple logo and the spinny thing... and then it turned to this:

do not enter! apparently!

I let it hang like that for fifteen minutes or so before I got bored/antsy. I then forced shutdown with the power button and started it back up - same song 'n' dance. It's been doing this for thirty minutes or so now. The machine is hot and whirring away about something, but no progress is being made. It all feels very foreboding.

Do Not Enter can't be a good thing, but as far as I can Google, there are a bunch of different things it could mean. What do you think, Apple.SE?

(FTR, I have some experience with software and troubleshooting, but very little with hardware maintenance/repair/fiddling about.)

Update: As far as I can tell from Googling around and from friends' tips, this denotes an issue reading or communicating with the hard drive. I've made a Genius bar appointment for this afternoon and will report any useful information that comes out of that meeting.

Post-Genius-Visit Update: I visited the geniuses today and, long story short, I am getting a new hard drive. They were unable to mount my drive, and Disk Utility was able neither to repair it nor to reformat it. The Genius I spoke to believed that the fact that this happened to my computer immediately after installing Lion is a coincidence, or that the drive was on its last legs and that Lion was the proverbial backbreaking straw, not that the problem was caused specifically by the installation. One of the other Geniuses around also mentioned, though, that he'd seen a few cases like mine today, including the Lion part. Does this sound odd to anyone else? If not, I'll post & accept an answer saying a new HD is the solution - assuming I can install Lion on the new one without it becoming all borked up...

To be continued, I suppose.

  • Have the same problem with a Mac Pro desktop. I downloaded Lion and after the download I pressed continue. Computer restarted and now hangs on white screen with Apple logo and wheel spins. Tried to reboot with Snow Leopard disk - no success. Need help!
    – user8079
    Jul 21, 2011 at 13:49
  • +1 I attached my "emergency" hard drive via USB and rebooted from that drive. I ran Disk Genius and Disk Warrior. Each program seemed to fix the drive but it still hangs. I tried deleting the entire Lion upgrade folder and app and restarting which brought me back to Snow Leopard. So it seems my disk isn't broken. I re-downloaded Lion again overnight thinking I just had a bad package of files. No luck with the fresh download. I was able to install on my MacBook Air just fine.
    – user8095
    Jul 21, 2011 at 16:18
  • Just want to note that I'm away from home for a few weeks and without most of my equipment, restore disks, etc - or else I wouldn't have had to go all the way to an Apple store just to give Disk Utility a shot!
    – hairboat
    Jul 22, 2011 at 2:42
  • Try holding down command+v on startup to enter verbose mode. This logs everything the OS is doing on startup, and is really useful for sorting out startup issues. Post the results here... Jul 22, 2011 at 23:53
  • The Genius guys and I did that. Wish I'd thought to try it before I took it in so I could've posted the output. Oh well - thanks anyway for the tip.
    – hairboat
    Jul 24, 2011 at 14:14

1 Answer 1


What went wrong was your hard drive is failing. The system cannot find a valid bootable system. You can test this by booting to an external drive (which looks like might have to wait for getting home or to the shop)

If the failure is happening fast - you just had bad luck and it would have failed within days no matter what. Get your stuff off and be glad you got things out before the "house burns to the ground".

If you had a slow failure, then the upgrade could have made things worse. This slow failure can often be made better by zeroing out the whole drive. Bad blocks get marked and for a while, it is reliable. You might buy some months or a year, but it's starting to fail.

Did the technician let you know if she or he felt you had a crisis or a slow issue with the HD?

As an analogy, Imagine a large "house" made of four decks of cards and lots of levels. If the far left hand side is shakey but you only are adding cards to the right, it might stand for a long time. As soon as you touch the left, down it comes.

A system upgrade touches everything - and re-writes the core software needed to boot. Your mac just wasn't up to having critical files written reliably and the upgrade brought those errors to stark light.

Put another way, Lion is running on millions of macs.

Sadly for you, something about your mac was different than most and the results quite painful to your productivity. The good news is many are going through the same pain - discovering how fragile HDD/SSD storage can be when a critical file fails to get written correctly.

I hope you get everything fixed, lose no data and can start enjoying Lion.

  • 1
    It looks like I'd been adding cards to the right side of the house for a while, and Lion touched the whole house, as you described, and knocked the cards all over the place. My computer's in the shop getting a new drive this weekend. Once I've got it back and have restored the data and completed the Lion install, I'll Accept this answer - gonna hold off for now just in case.
    – hairboat
    Jul 23, 2011 at 3:52
  • 1
    Success! Sent from my MBP running Lion
    – hairboat
    Jul 28, 2011 at 4:05

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