Macbook Air Startup Disk Error

[Hectorss]

From last few days i was getting an error message on my screen saying that the startup disk was almost full for some days. I was shocked about this issue because i did not have any issue regarding the start up of the disk. Then i decided to erase all unnecessary documents from my computer, but when i attempted to do so my computer got blocked. After that I shut it down and restarted it to check what exactly the problem is. But when I restarted it, a new message saying my "startup disk was full popped up". Then a message asking me for my login details popped up and it just shows my screen saver nothing else. It doesn't allow me to do anything at all.. What should I do in this situation? I have lot of assessments that I need to turn in this week but due to this problem I am not able to access them.
Please help me guys!!!!!

[Antonio1]

I have one solution for this issue. You can simply go to the Safe Mode and try it. It might allow you to boot and free up some space. If it works , then you may open up somewhere around 20% free space. Once you are finished with that, then you can run Repair Disk: Boot from install disc (insert disc->restart->immediately hold down c key and keep holding it until you see “Preparing Installation” message popping up )->At first screen select the language and click Continue button-> Then click on the Utilities Menu in the menu bar->then open Disk Utility->select your HD in the panel on the left side->click Repair Disk at bottom of main window. Run this at least twice, and keep running it until a message pops up saying that “appears ok” twice in a row. If this doesn’t work, then you may need a stronger utility than this such as Disk-Warrior. After performing these steps you will be able to get out of this problem for sure..

[Carlos16]

I own a Macbook Air laptop. It seems to work fine, but when I run Disk Utility program and then clicked on "Verify Disk" option, it reported some 'file system error'. After that the "Repair Disk" button was disabled, because this is the startup drive. So, I restarted with the Mac OS X Install Disc and again ran Disk Utility program. But when I ran "Repair Disk" program, I got this output:
Verify and Repair volume "Macintosh HD"
Checking Journaled HFS Plus volume.
Checking Extents Overflow file.
Checking Catalog file.
Invalid node structure.
Volume check Failed.
Error: Filesystem verify or repair failed.
I don't know what should i do?? Is there anything else I can do to try to repair the file system..

[Crespin]

MAC Operating System X will use hard drive space for virtual RAM, in turn which tales large amount of disk space. However it should get cleared on a reboot. Their may also be some problem with the log files going out of control. Try to run a cleaning program such as Onyx. Filevault can also be one of the cause for low-space issues. 3 GB memory is not enough free space for any comfortable operation but you should really have more than 10 GB free for virtual RAM for easy operation.