I am running the Boot Camp Assistant on El Capitan. Whenever I reach the third screen, titled "Save Windows Support Software", on which I can select an storage medium to save the Windows support software to, I am shown the following error message upon selecting a disk and hitting "Continue": "Please format the USB drive as single FAT partition.".
I am using a Transcend 16GB USB drive. I have formatted it as FAT through Disk Utility. I have tried every possible partition scheme. I have also tried formatting the drive as Ex-Fat, again in combination with all three partition schemes. I keep seeing the error message. There seem to be a fair number of people who have encountered the same issue, and for some it was resolved by formatting the drive as FAT with a MBR partition scheme. For others however this did not work.
Any advice on how to make the Boot Camp Assistant accept my USB drive would be much appreciated.
Best Answer
After some trial and error, I finally figured out what the problem was and found a solution. Hopefully this will help those who come across this thread with the same problem.
The problem: Reformatting using Disk Utility did not create a child partition, but only formatted the whole drive as FAT. In Disk Utility one can derive this from the "Partition" button being greyed out when the USB drive is selected. In Terminal, the
diskutil list
command shows the USB drive having only one DeviceNode (labelled0
).The solution: Reformatting the USB drive using
diskutil
in Terminal. This is the command line equivalent of Disk Utility, but unlike its GUI Counterpart, it creates a child partition, which in turn solves the error thrown by Boot Camp Assistant.WARNING: Proceed with caution! If you have never used a command line interface before, you might want to ask a tech-savvy friend for help. I take no responsibility for the outcome of this. If you fry your hardware in the process, that's on you. Good luck!
Stepwise:
diskutil list
and hit enter./dev/diskX
. If you have only one external drive connected, this should be easy to figure out (hint: behind the identifier it says(internal, ...)
or(external, ...)
).diskutil partitionDisk /dev/diskX 1 MBR fat32 NAME 8G
. Replace/dev/diskX
with the identifier of your drive which you obtained in the previous step. ReplaceNAME
with the name you want to give the partition (which essentially doesn't matter). Make it all CAPS to avoid problems. Replace8
in8G
with the number of Gigabytes you want your partition to have. It's easiest to just go with the total size of your USB drive.0
, of typeFDisk_partition_scheme
, and1
, of typeDOS_FAT_32
and with the identifierdiskXs1
whereX
is a digit corresponding to the identifier you found in step 3.