I was installing El Capitan from Snow Leopard. After taking a few hours to start installing, it popped up and said the installation failed, and to click restart to try again. I clicked restart, and it restarted, then asked me what disk I wanted to install El Capitan on, and I picked Macintosh HD and it said not enough space - which surprised me, because I had checked before downloading El Capitan and starting the install that I definitely had enough space. I think the partial install had taken up a lot of space. I couldn't get back to my normal functioning Snow Leopard, every time I turned on the computer it would take me to the El Capitan install screen.
After getting no help from Apple Support, who told me I was going to need to erase my hard drive, I started Googling and found this. Thanks to @klanomath for getting me started with a solution that worked.
- Turn off computer using the power button.
- Hold down command+R, click the power button, keep holding down command+R until the Apple logo appears, let go. This starts recovery mode.
- On the very top of the screen, went to Utilities>Terminal.
The goal was to find big files I could delete.
To get to your main disk, if it's called Macintosh HD. The back slash you have to put before any spaces:
cd /Volumes/Macintosh\ HD/
To get list of everything in the folder you are in:
To get to my documents, use:
cd /Volumes/Macintosh\ HD/Users/username/Documents
If you need to, you can navigate around by doing:
cd /Volumes/Macintosh\ HD/
it shows you a list of folders, then get to the subfolder by either
cd /Volumes/Macintosh\ HD/Subfolder/ (typing full path)
cd ./Subfolder/ (shortcut where the
. is wherever you are now).
To go up a folder use
Then once you're in a subfolder with some files you're considering deleting, you can use the following to get a list with file sizes, so you can identify the big ones:
After I navigated around a while and couldn't find many big files, I googled and found I could do the following to get a list of paths of all files bigger than 500 MB:
find / -size +500000 -print`
Then I could re-navigate to them so that I could delete them. To delete a file use:
(be careful you type the file name right, you don't want to accidentally delete other stuff, this can't be undone)
To check the directory you are currently in use
I deleted some big video files I had and freed up several GB of space. Check the space with
Look for Macintosh HD in the list (if that's the name of yours) and there should be some stats about % of space full, GB used vs. free, etc.
Then, in the very top left of the screen, the picture of an Apple, I clicked that and clicked "restart," my computer restarted, started the El Capitan install again, took forever, but actually finished! And now I am happily running El Capitan and did not need to erase my hard drive. I will be backing up some of my stuff now, lesson learned :)