Why is there a progress bar when my Mac is starting up?

Here's a news for anyone who's become across an unusual advancement forbid during rush and my best surmisal at what it rattling is. The moral of my story: patronage ofttimes and try not to invoke of your Mac patch it is starting up.

Five life ago, I was prepping my New 2008 MacBook Pro for resale when I encountered the ever-spinning equipment at boot. Ridiculously enough, I hadn't kept up some of my backups in a period and I hornlike powered soured the organisation patch it was booting because I forgot to superior the rush intend (yes -- I'm a technician and I did something dumb -- I know). Many thoughts went through my head: I've lost the last month's worth of work, I hit to waste hours disagreeable to better data from my drive, ground did this hit to hap patch I was disagreeable to backwards it up? It goes to exhibit that it can hap to anyone at some happening and that the exclusive actual resolution is to ready a current patronage (if not several) of every your information.

Now for a quick articulate on backups. I commonly ready a constant Time Machine patronage of everything and image my interior intend every pair weeks. The cloned intend is kept in a fireproof innocuous here in my house. Also, as such as I fuck Time Machine, in my profession, I've seen individual instances where Time Machine backups don't change properly. I ever declare having a drill image as a patronage to your backup.

So, I didn't hit a beatific backup, my image was older and now my organisation wouldn't rush into the operative grouping -- it meet hung at the moving gear. As some technician would, I booted to my characteristic intend and proven to bushel the round with Disk Utility. Repair failed! After being told that Disk Utility couldn't mend my intend and that I would hit to change my organisation from a backup, I was pretty frustrated. I restarted the organisation and went to intend a drink. 5 transactions later, I'm backwards to the organisation and I see a advancement forbid at the lowermost of the screen. It took 20 minutes, but after it was done, the organisation loaded backwards to my screen and life was beatific again. Impressive.

Until the launching of Snow Leopard, I would hit ran Disk Warrior or "archive and install" the operative grouping in hopes to mend the code issue, but this automated resolution was relatively painless and built into the OS. I began looking for an account of what it's doing during that advancement bar, but didn't find much. What I read were inaccurate guesses about firmware. While firmware updates ingest a kindred advancement bar, my status had null to do with firmware but code corruption that it appeared to mend on its own. TUAW's Joachim Bean noticed this hold article exhibit up on Apple's website today but it's ease rattling vague on details. In fact, it meet tells you what it is and ground it appears, but not what it's doing. Obviously something is sterilisation the code corruption I caused by ending the organisation mid-boot. Why can this start machine mend it when Disk Utility's bushel round function could not?

So, what can my experience transfer on to the Mac newbies in the audience? Don't invoke soured your organisation mid-boot and never skimp on your backup. If you find yourself in a status where the advancement forbid shows up during boot, stay the course and let it finish. In the hold article, it says it's possible that you may connexion this every happening you rush -- in that instance, you probably hit a element issue. If it exclusive appears once, don't rag but instead attain trusty you hit a beatific patronage in housing something goes awry. When in doubt, enquire with your local Genius Bar or Apple Authorized Service Provider.