7 Replies Latest reply: Jan 25, 2013 8:04 PM by GeekBoy.from.Illinois
Groy99 Level 1 (0 points)

I am trying to install Windows 7 and when it gets to the point of copying the files to my 8gig USB drive it craps out and says unable to write to the drive.


Is there any tips or tricks that I should know about? Should I be using a Dual Layer DVD instead of the USB drive?


Thanks for the help.

iPhone 5, iOS 6.0.1
  • GeekBoy.from.Illinois Level 4 (2,805 points)

    From what I recall, Windows 7 only needs about 2.5-3GB of space to create the bootable install media.  What method are you using to try to create the bootable USB stick, and from what source are you getting the install files to put on the USB stick?

  • Groy99 Level 1 (0 points)

    I am using an ISO file to create the Windows 7 bootable USB stick via Bootcamp for Mac. All of my operations are done throught Bootcamp that came with the most current OS on my Macbook Pro (December 2012).


    Thank you.

  • Csound1 Level 8 (46,870 points)

    Groy99 wrote:


    I am using an ISO file

    What is the filename and what is the size of this ISO.

  • Groy99 Level 1 (0 points)

    Size of the file is just over 4gig. Not sure of the file name right now as I am at work.  If there is a specific file name that I need to have than I can just rename it.


    Also I'm pretty sure when I get my error it is when Boot Camp is copying drivers for windows and not when it is accessing the Windows 7 ISO file.

  • Csound1 Level 8 (46,870 points)

    4G is the correct size for the Windows ISP, but still need another thumb drive, that's for the drivers, and they are less than 1G


    Stop what you are doing and read the Boot Camp documentation carefully, you are doing it wrong.


    Backup your machine before going any further.

  • Groy99 Level 1 (0 points)

    If memory serves me, because I am not at my Mac, you can use the USB for the ISO file or a Dual Layer DVD. I have plugged in a 8gig USB for the ISO and a 2gig USB for the windows drivers so I'm not sure what is the problem.


    I am picking up the Dual Layer DVD's tonight and will try that path this weekend.


    Would there be any other reason that I'm getting the error?

  • GeekBoy.from.Illinois Level 4 (2,805 points)

    Well, if you have partitioned/formatted your USB drive using a Windows computer, it may be in an NTFS format, which Mac can't write to natively.  I also know that some USB drives have a "hardware write-protect switch" to make the drive read-only.  If your drive has one of these, it could be switched to the wrong setting.  I've even heard from some people that MacOS Lion (and newer) cause their "write protect switch" to act as if it is "on" no matter if the switch is on or off, but if the switch is somewhere in between, it seems to work for them. There is an outside chance that you could be impacted by something like that.


    I know I've downloaded Windows 7 ISO files from Microsoft Volume License servers and from MSDN at work, and all of them have been less than 3.5GB, so I do wonder what all is on your 4GB ISO file to add an extra 500MB of space to the ISO file.  Hopefully your ISO is from a reliable source and doesn't come with its own pre-installed security risks...

  • Csound1 Level 8 (46,870 points)

    GeekBoy.from.Illinois wrote:


    I've even heard from some people that MacOS Lion (and newer) cause their "write protect switch" to act as if it is "on" no matter if the switch is on or off,

    Stop listening to 'some people' their info is BS.