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

That happened to me some times when I got any kind of firmware update...

Hey guys,

This screen your seeing is new with Snow Leopard. Before in 10.5 and previous, when going into safe boot the OS would just show the spinning gear, but with Snow Leopard they introduced this new progress bar. Some users were correct in mentioning that it is doing an fsck check in the background, but several other things are also going on. I used to work @ AppleCare and can tell you a lot of behind the scene things are removed, generally temporary cache files etc. If you want the full background processes this excert from apple's support page (http://support.apple.com/kb/HT1564) should explain things pretty well:

Starting up into Safe Mode does several things:

- It forces a directory check of the startup volume.
- It loads only required kernel extensions (some of the items in /System/Library/Extensions).
- In Mac OS X 10.3.9 or earlier, Safe Mode runs only Apple-installed startup items (such items may be installed either in /Library/StartupItems or in /System/Library/StartupItems; these are different than user-selected account login items).
- It disables all fonts other than those in /System/Library/Fonts (Mac OS X 10.4 or later).
- It moves to the Trash all font caches normally stored in /Library/Caches/com.apple.ATS/(uid)/ , where (uid) is a user ID number such as 501 (Mac OS X 10.4 or later).
- It disables all startup items and login items (Mac OS X 10.4 or later).
- Mac OS X 10.5.6 or later: A Safe Boot deletes the dynamic loader shared cache at (/var/db/dyld/). A cache with issues may cause a blue screen on startup, particularly after a Software Update. Restarting normally recreates this cache.

Taken together, these changes can help resolve software or directory issues that may exist on the startup volume.

Its most likely the EFI update that was just released for the MacBook Pros. I used to work at Apple as a Mac Genius, and usually the progress bar is for when you are updating the EFI which is essentially the framework that the operating system is built.

Josh,

For cloning your drive, is there an app you recommend? I do a time machine backup once a week but also drag and drop a lot of my important files to a couple of my backup drives. Was wondering what you used for that?

Thanks!
c

Josh,
while your article is a nice attempt to help some people experiencing the prog bar ish, you would have better served them by offering a more constructive troubleshooting methodology as has been mentioned already. I do not know how long you have been using/servicing macs, but apparently not long enough i'm sorry to say.

The best advice to give noob's would be Not to come here for help.
www.macosxhints.com would be a better place...

sorry, truth hurts.

Nice job using LOLs as punctuation, KiYi. Taking a look at your comment history, I count about 9 negative insulting comments for every 1 positive one.

Keep on being awesome.

This happened to my GF's Macbook last week, Disk Utility was of no use, and the progress bar was there at every boot-up. Wifi was non-functional and every time I changed to a static IP or deleted and created a new location it would revert right back after Applying. I ended up backing up data and doing a fresh install of SL...works flawless now.

I don't know how long Josh Carr has been using Macs, and it doesn't interest me either. What does matter is the low standard of some of the responses, especially as Josh says:

So, what can my experience pass on to the Mac newbies in the audience? Don't turn off your computer mid-boot and never skimp on your backup.

He isn't writing for the more experienced user here, he's speaking "TO THE MAC NEWBIES".

What would be useful is if people who already know about this make some constructive contribution to help out any newbies lurking here.

Given the rising number of rude and downright insulting comments, I wouldn't be too surprised if TUAW started moderating posts...

Freedom of speech is not about insulting or swearing at others.

Pressing SHIFT while booting does the same thing manually

I had this happen to me about a month ago. My MacBook Air hung up in normal operation, and I had to hard stop it. On restart, the progress bar appeared, completed about 10 % of the way, and then started over again. This time, at the 10 % mark, it simply powered itself off. I booted from the Snow Leopard CD, and ran disk utility. The drive was corrupted, and could not be repaired, so I reformatted it (which worked), and restored from a Time Machine backup (which also worked).
Unfortunately, now, the same problem has returned, and it is at the Genius Bar. The telephoned to say, that after installing a new drive, it still would not boot, and that it was 'probably' a logic board problem. We'll see.