So i've had a few problems over the last few days trying to upgrade from 10.8.5 to 10.9.2.
Unibeast failed to complete creation of the installer
Migrated to clover to attempt install by running the install maverick .app and booting 'install maverick from mountain lion'
It took forever to boot and when it got to the installer screen but before any writing came up it froze and was just a grey screen with a
in the top left corner.
I tried following this guide, created the installer usb but the installer would not load up.
I adapted the instructions in this guide by adding a 10gb partition on my hard drive, using the terminal commands and choosing this partition (took 1 minute to do bearing in mind I have an ssd, maybe 10 mins for standard HD), ran the clover installer on this partition, added the EFI folder & Config file but using the efi boot file from the HD.
This again resulted in the frozen screen with the beachball.
I tried booting the EFI file from the installer usb and tried the installer from my 10gb partition and it booted & installed flawlessly.
Install took 32 minutes which is probably faster than using the usb stick. Maybe this should be adapted as an os x upgrade method??
On conclusion, there seems to be an issue with the clover efi install on my hard drive & the installer made on disk.
Make of that what you will.