I am close to my Mac. It’s a serious relationship. So when my iMac locked me out of the login screen and threw away the key, I was in various stages of grief. Denial, anger, and depression. But I remained calm and solved the problem without an OS reinstall. Here’s how it happened.
It was a Sunday afternoon, September 25. I wasn’t in the mood for the NFL yet and held my breath, suspecting the Broncos would lose again. (They did.) So I decided to work on some iMac housekeeping.
Previously, I noticed that I had a stray Input Manager in /Library/InputManagers. I knew that these are bad news items, and I thought I had cleaned them all out. I even chatted with our Dave Hamilton after MacGeekGab #352 about how useful his podcast was to remind me about them. (If you want to read more about these tricky little critters, here’s the full story by Adam Engst.)
However, just before I cleaned out that folder, I had noticed that Lion (10.7.1) was being stupid about displaying the disk space used on my Time Machine external drive. (LaCie, d2 Quadra). So I did a Get Info on the Time Machine folder itself. This takes some time, so I went back to my clean up of the InputManagers folder. Finally, the Get Info was taking so long, I just decided to go ahead and reboot.
After the login screen came up, I was locked out. No keyboard or mouse response whatsoever. I was shoved out the door, and my Mac had thrown away the key.
Where you’re locked out here, it’s a scary moment.
Believe me, it’s a very, very bad feeling.
Of course, my first reaction was suspicion of a loose USB cable to my keyboard, but deep in my heart, I knew this wasn’t going to be the answer. It was fine 20 seconds ago. And indeed, that wasn’t it. Guessing that Lion had gone wonky, I rebooted again.
Same result. Oh, crap. I took a deep breath.
My next guess was that my fiddling with an input manager had caused a problem. I didn’t believe that either, but I figured that putting things back the way they were before the reboot is never a bad idea. But how to do that? After reflecting for a second, I remembered that I had been using screen sharing from my MacBook Air, and it was all set up. So I went to the MBA and, sure enough, I was able to log in remotely. I went ahead and put the “1PasswdDlM” file back and rebooted the iMac from the MBA.
OS X Screen Sharing can be a life saver.
Same result. I was still locked out. I sat staring at my iMac thinking about my options, whether I wanted to do a Lion restore, recalling the state of my Time Machine backup and pondered how my Sunday was soon to become absolutely shot. Forget about the Bears and the Packers.
As I sat, with head in hands, glaring at the Mac that had unceremoniously jilted me, my eyes wandered over to the LaCie external drive. The activity light was still continuously flickering. That shouldn’t have been happening after a reboot. WTF.
From deep in my subconscious, after 27 years of using Macs, I recalled that maybe, just maybe, a FireWire drive that’s hung up can block keyboard input. Don’t ask me how I knew that. It was just an intuitive guess. So I reached over, turned off the drive and rebooted.
Login was normal.
At this point I felt like I was half idiot and half genius. My smugness was quickly erased by the realization that had I reinstalled Lion, that attempted fix would have failed spectacularly (had I not cycled the external drive).
I can offer some humble recommendations.
- Don’t obscure the disk activity light on your external drives. That light is a great diagnostic tool.*
- Leave Screen Sharing on. (System Preferences -> Sharing.) That way, if you have another Mac, you can access a sick Mac with a ful GUI interface.
- If you have a problem similar to this, don’t rush to reinstall the OS. Even if you’re in a panic mode. Sit back. Ponder. Make some tea. Try to think of things that you can do that don’t involve a reinstall. For example, try disconnecting all external devices, except the keyboard, plug in a wired mouse and reboot.
This time, I got lucky. Maybe, just maybe, it’ll help you someday.
Oh, and by the way. Apple? Is there a way to fix this long-time Mac problem?
* Disk drive makers: Did you hear that? Please don’t try to save 50 cents by deleting that light, tied to disk activity. We need it.