MacBook Air (11-inch, Mid 2012): "Free up space on Drive C" alert during Windows 8 upgrade
When upgrading from Windows 7 to Windows 8, a "Free up space on Drive C" message may appear on MacBook Air (11-inch, Mid 2012) computers with 64 GB flash drive.
Use a full version to install Windows 8 instead of an upgrade version. Upgrade versions will not install properly because the 64GB flash drive can only allocate 34GB of space for a Windows partition which is not enough free space to accommodate an upgrade installation.
To install the full version of Windows 8:
Back up your data from the Windows partition.
From the Go menu, select Utilities
Double click on Boot Camp Assistant
Click Continue, then place a checkmark next to "Remove Windows 7 or later version" to delete the existing Windows 7 partition. Warning: This will erase your existing Windows 7 partition. Be sure you have a backup before proceeding with this step.
Use the Boot Camp Assistant to install a full version of Windows 8.
Once installation completes, restore your data from your backup.
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