Boot Issues

I'm attempting to boot a copy of Windows 7 from a legal and legitimate ISO file that is stored on a USB drive. I have a serial number and product key, etc but I am still running into the NTLDR missing error. I've tried several different boots including FAT32 which does not work at all and NTFS which is usually where I receive my NTLDR message and using UNetbootin which basically prepares your USB drive to become bootable. With the last option I either get a UNetbootin infinite loop or continue to get the NTLDR error. Another issue I have is that my hard drive died so I didn't get a chance to make a back up and I only have access to a Mac and a Windows XP machine with no internet. This is making it virtually impossible to create a bootable USB disk (using Windows USB/DVD tool) because neither of the other machines at my disposal can run that program. I can not burn a DVD with either of these extra computers as well, so that limits my ability too.

Nope, this Mac cannot burn DVDs. Trust me I would have already been to Target or Office Max today if that option would work. Unfortunately, the only computer that has the ability to burn DVD's is the one with a dead hard drive.

Joe S

Excellent Member
MS had a tool to burn a Windows 7 ISO to USB. Check at MS I don't know if it would work on a Mac.


Excellent Member
Microsoft Community Contributor
Making a flash drive for Windows 7 requires the following steps. Do you have something that can accomplish them?

Clean the drive to remove configuration data, and diskpart is normally used for this.

Create a partition and format using Fat32, then make it active, assign a drive letter and copy over the files from an Install DVD, or a mounted .iso file.

If you want to use UEFI, you will also need to create a folder in the EFI folder and add a file called bootx64.efi which is a renamed bootmgwf.efi file. So you have EFI\boot\bootx64.efi and that file is on all x64 Windows 7 installs in the Windows\Boot\efi folder or you can use 7 Zip to pull it from the .iso file.

The Microsoft .iso to flash drive utility will make a bootable flash drive as long as you do not need UEFI. But the Microsoft utility will not work from a UEFI install because it cannot run bootsect.exe, which defines the boot loader, NTLDR or Bootmgr.

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