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Shawn, Computer Engineer
Category: Mac
Satisfied Customers: 275
Experience:  15 years of Mac software and hardware troubleshooting experience, 10 years of programming experience
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i got a message that my start up disk is almost full . now

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i got a message that my "start up disk is almost full". now mac OS won't open. how can i fix it?

Can you tell me what kind of Mac you have?

Do you have another Mac available to you that you could help recover files with, if necessary?

Do you have your original Mac OS X install disk that came with your computer?

Thanks! Kind regards,


Customer: replied 8 years ago.

i have a mac book pro.


i do not personally own another mac, but i can access a friend's mac if necessary.


i do not have the install disk


Okay. There are a few things that we can do without the install disk, but if you have a way of finding it then it's an awfully handy thing to have for a lot of Mac troubleshooting.

First, I'd like you to try and boot in Safe Mode, by following these instructions:

Let me know if this works at all. It may take up to a half hour to boot in this mode, so give it some time.

If it boots, go ahead and try rebooting again in regular mode.

Let me know how this works for you, and in particular what you see during startup (do you see the Apple icon? Do you see the desktop? Where does it stop loading?)

Kind regards,

Customer: replied 8 years ago.

i held down the shift key immediately after the tone, but it did not show "spinning gear" or safe mode. it went directly to the windows portion of the hard drive. during start up i saw a grey screen, then a black screen with a blinking cursor on top left, then windows start up. no apple icon and no desktop.


Can you change the startup device to be Mac OS X instead of Bootcamp, and then try booting in safe mode again?

Customer: replied 8 years ago.
i'd love to, but i don't know how. before the whole "start up disk" error incident, it always started in OS. it never went automatically into the boot camp thing.

Aaahhh okay, resetting the PRAM should clean that up then. Please follow these instructions:

Customer: replied 8 years ago.
if i do this, will i lose access to my windows partition? this is the ONLY internet access that i have and i will be totally screwed if that is lost too! PS. you're awesome by the way!

Thanks :-) We'll get this problem figured out for you!

You won't lose access, but here's how to get back into it.

Instead of holding down the shift key to boot into safe mode, you can change your boot device by holding down the OPTION key immediately on startup. You should see a dialog with pictures of at least 2 hard drives, one that will be labeled Mac OS X and another that will be labeled something like Bootcamp. Select the one you want to try and boot from.

Just so you are sure that you can get back into Windows, I recommend restarting now and trying to get into this boot manager BEFORE resetting the PRAM. If it works and you can get in, then you can always get back there, even after resetting the PRAM.

Good luck! Let me know how this works for you. Kind regards,

Shawn :-)
Customer: replied 8 years ago.
sweet! i already know how to do that! that's how i always did it before. i'm going to do the PRAM thing now, and increase my bid:) i know you need to get paid!
Awesome, thank you very much, I appreciate it! :-) Let me know how it works for you.


Customer: replied 8 years ago.
um, i swear i'm not a dumb girl, but can you please tell me what the "command" key is?

No problem. The command key is next to the option key and has icons of a 4-leaf clover and an open Apple on it.


Shawn :-)

Customer: replied 8 years ago.

ok, so i started the computer, held the keys and released them after the second tone. i got a grey screen and a third tone and then it went back to windows on its own. i'm still locked out of OS. is it possible to designate more gigs to the the mac HD from the windows side?

Hello again,

Okay. Unfortunately we can't transfer hard drive space from the Windows side without a significant amount of work and the install disk. The hard drive filling up can also cause damage to the Mac operating system that we cannot repair without the install disk, but there is one more thing we can try first.

You'll need your friend's Mac and a FireWire 6-pin to 6-pin cable (you can find one at Best Buy). The ends will look like this:

Once you have those,

1) Connect the Firewire cable between the Macs
2) Start up your friend's Mac
3) Start up your Mac while holding down the T key
(More information: )

This will turn your computer into an external hard drive that you should be able to see on your friend's Mac. Once you're there, you need to copy off and/or delete files from the hard drive on your Mac to free up some space. You should have at least 1 gigabyte free on the drive for the operating system to have a comfortable breathing room. Make sure to empty the trash when you're done, and try to stay away from the system files when deleting things. If you don't know what a file is for, don't delete it.

Once you're done and have free space, drag your hard drive into the trash can on your friend's Mac to unmount it, shut it down, and try rebooting again while holding down the shift key. If that doesn't work, try holding down the option key to select Mac OS X.

Also, any troubleshooting steps beyond this are going to require an install disk. If you know someone with a similar model of computer to yours then you can use their install disk, otherwise you'll need to buy a new one.

Let me know how this works for you and I'll help you as much as I can. :-) Best,

Shawn and 3 other Mac Specialists are ready to help you
Customer: replied 8 years ago.
thanks! i will try this later on today! i truly appreciate your help!

Great, let me know how it works for you! Thanks for the Accept. :-) Best,