Finder says I have 20GB free. Why does Bootcamp say I don't have 10GB free?
I'm trying to partition my Macbook Air's SSD for dual-boot with Boot Camp (which I've done several times before)... however, it's not seeing 10GB free, yet I have 20.56GB free as per Finder, and Disk Utility sees 10.9GB unused space.
What's going on? How can I force this to work? Can I use disk utility and image to an external drive and restore? Would vastly prefer an easier method of course
Solution 1:
You may be just reading the wrong figure in Disk Utility, have a look at the quote below from the apple discussion forums
Disk Utility will show two different "free" readings, depending on where you look.
Sounds odd, but they're for different purposes. The larger figure, which the Finder and other things will use, is the total free space available.
The second is the amount of free space available for a new partition. It's shown when you select the top line for the drive, click the Partition tab, then select a partition, the "Available" amount may be smaller.
This is because partitions, unlike folders, must occupy contiguous space on a disk. The data on your OSX partition is scattered over it, not all nicely packed together. That's normal, as you add, update, and delete files, not every nook and cranny is used again immediately.
But whether there's 7 GB free or 18, that probably isn't enough to be adding a partition; it's probably too little for OSX to operate well. There's no "hard and fast" rule, but you should always have at least 10 GB or 10% of your OSX drive free; many folks say 15% or more.
You could back up your drive (on two different HDs, to be safe), reformat it to 2 parttions, then restore the backup. But it's going to be very tight, and you'll likely have performance problems because of it.
Try to delete anything you don't need, and/or offload stuff you don't use often and delete it.
Solution 2:
Boot camp wants 10GB of continous space, if there is even a little file somewhere cutting that 10gb it shows the error message.
How I got around this issue:
Open up disk utility and shrink your primary partition down by about 12 GB, in effect making 12 GBs of un-partitioned space. (WARNING: this might kill some data at the end of the disk but for me everything seemed to be ok)
Then I repartitioned the primary partition back to the full amount, in effect creating 12GB of contiguous empty space.
Run Boot Camp Assistant and no more "10 GB" error message!
Alternatively I though about looking in to defragging the hard drive.