How can I free up storage on a Macbook air 11-inch, mid 2012?

Freeing Up Space on The Hard Drive

1. See Lion/Mountain Lion's Storage Display.

2. You can remove data from your Home folder except for the /Home/Library/ folder.

3. Visit The XLab FAQs and read the FAQ on freeing up space on your hard drive.

4. Also see Freeing space on your Mac OS X startup disk.

5. See Where did my Disk Space go?.

6. See The Storage Display.

You must Empty the Trash in order to recover the space they occupied on the hard drive.

You should consider replacing the drive with a larger one. Check out OWC for drives, tutorials, and toolkits.

Try using OmniDiskSweeper 1.8 or GrandPerspective to search your drive for large files and where they are located.

So why is this here in Boot Camp forum? are you using Windows or wanting to install Windows using Boot Camp?

With the Air not sure about internal upgrades but were you using TimeMachine? maybe you have some pending backups.

Don't use it until you can figure it out. That means boot into Recovery Mode and repair the disk for one thing. Running a Mac on zero free space is asking for the directory to your files to totally fail. Less than 10% free is dangerous (should alert when you get to 10GB free space if it were smart).

Learn how to clone your system.

Boot Camp must be able to allocate a contiguous block of space on the drive. If it cannot find 10 GBs of contiguous space, then you cannot create the Windows partition.

You will have to backup your OS X partition to an external drive, boot from the external drive, use Disk Utility to repartition and reformat your hard drive back to a single volume, then restore your backup to the internal hard drive.

1. Get an empty external hard drive and clone your internal drive to the external one.
2. Boot from the external hard drive.
3. Erase the internal hard drive.
4. Restore the external clone to the internal hard drive.

Clone the internal drive to the external drive

1. Open Disk Utility from the Utilities folder.
2. Select the destination volume from the left side list.
3. Click on the Restore tab in the DU main window.
4. Check the box labeled Erase destination.
5. Select the destination volume from the left side list and drag it to the Destination entry field.
6. Select the source volume from the left side list and drag it to the Source entry field.
7. Double-check you got it right, then click on the Restore button.

Destination means the external backup drive. Source means the internal startup drive.

Restart the computer and after the chime press and hold down the OPTION key until the boot manager appears. Select the icon for the external drive and click on the downward pointing arrow button.

After startup do the following:

Erase internal hard drive

1. Open Disk Utility in your Utilities folder.
2. After DU loads select your internal hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. SMART info will not be reported on external drives. Otherwise, click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, set the partition scheme to GUID then click on the OK button. Click on the Partition button and wait until the process has completed. Do not quit Disk Utility.

Restore the clone to the internal hard drive

1. Select the destination volume from the left side list.
2. Click on the Restore tab in the DU main window.
3. Check the box labeled Erase destination.
4. Select the destination volume from the left side list and drag it to the Destination entry field.
5. Select the source volume from the left side list and drag it to the Source entry field.
6. Double-check you got it right, then click on the Restore button.

Destination means the internal hard drive. Source means the external startup drive.

Note that the Source and Destination drives are swapped for this last procedure.

How to create an OS X Lion installation disc MacFixIt

Migration Assistant Update for Mac OS X Snow Leopard

http://www.apple.com/support/lion/installrecovery/

http://reviews.cnet.com/8301-13727_7-20080989-263/how-to-create-an-os-x-lion-ins tallation-disc

http://www.coolestguyplanettech.com/how-to-make-a-bootable-osx-10-8-mountain-lio n-disc-or-drive-from-the-downloaded-mountain-lion-app/

How to clone your system:

http://macperformanceguide.com/Mac-HowToClone-backup.html

http://macperformanceguide.com/Mac-HowToClone.html

http://www.macupdate.com/app/mac/7032/carbon-copy-cloner

http://www.macperformanceguide.com/blog/2012/20120711_2-MacPro-internal-clone-ba ckup.html

Are you talking about the hard disk space on the MacOS side ?

If so, I ran into a similar symptom, it turned out I left the Time Machine "ON", it (time machine) always takes snapshot of system even though I deleted some large files (video). Just turned time machine "OFF", I regained about 80 GB of hardsdisk, which I knew it should be.

Hope, your case is same as mine.

tlmlvr