If a message appears telling you that your startup disk is almost full, don’t ignore it! The startup disk is normally ‘Macintosh HD’. Mac OS X needs free space to store system files, temporary files and to do it’s own housekeeping. You should aim to keep at least 10% of your disk free.
When you reach the last few hundred megabytes of free space, you will see the above message. Delete old/unwanted files, or move files onto an external hard drive and empty the trash. If you ignore the message, your Mac may freeze. If you shut the computer down with little or no free space, it may not start up again. If this is happening to you on a regular basis, we can advise on an alternative storage solution, such as fitting a bigger hard drive.