The other posts have good advice. I know this is a couple months later and it might not help the original poster out, but it could help someone in the future.
It is possible to use the Windows 7 ISO with both x86 and x64 on the same install file. Bootcamp 5 will see this as a x86 install file though and won't allow it to continue. To fix this just follow these steps.
1. Open a Finder window.
2. Navigate to Applications>Utilities
3. Control Click or Right Click on Boot Camp Assistant and select "Show Package Contents"
4. Open the Contents folder
5. Drag the file "info.plist" to your desktop (I also recommend saving it in another place as well in case you want to revert to the original)
6. Open info.plist on your desktop with a text editor
7. Find the field labeled as below:
<key>32BitSupportedModels</key>
<array>
<string>MacBook7,1</string>
<string>MacBookAir5,2</string>
<string>MacBookPro10,1</string>
<string>MacPro5,1</string>
<string>Macmini5,3</string>
<string>iMac12,2</string>
</array>
8. Time to find what your Mac is. Click the Apple in the top left hand corner and select About This Mac
-Click More Info...
-Click System Report...
-Under Hardware Overview, look for Model Identifier and copy it
9. With your Mac's Identifier copied, go back to your open info.plist file create a string at the TOP of the entries. So if your Mac identifier was "iMac13,2" then it would look like this:
<key>32BitSupportedModels</key>
<array>
<string>iMac13,2</string>
<string>MacBook7,1</string>
<string>MacBookAir5,2</string>
<string>MacBookPro10,1</string>
<string>MacPro5,1</string>
<string>Macmini5,3</string>
<string>iMac12,2</string>
</array>
10. Save and close info.plist. Drag info.plist back into the Contents folder and select replace. (You may have to authenticate and enter your admin password).
11. Start Bootcamp and it should allow you to use your Disk/USB with both versions. I wouldn't recommend installing the x86 (32 bit) version of Windows 7, but this will allow you to get to the point of the installation to select x64 (64 bit) if you have an ISO file with both 32 bit and 64 bit combined. Hope this helps.
Hi
I have done the above. Boot camp can't open after (Macbook air early 2014)
The weird thing is that I have Windows 64bit boot on a usb but bootcamp doesn't recognize it as a 64 bit version...
See message box from boot camp
Process: Boot Camp Assistant [692]
Path: /Applications/Utilities/Boot Camp Assistant.app/Contents/MacOS/Boot Camp Assistant
Identifier: com.apple.bootcampassistant
Version: ???
Build Info: BootCampAssistant-5706000000000000~80
Code Type: X86-64 (Native)
Parent Process: launchd [132]
Responsible: Boot Camp Assistant [692]
User ID: 501
Date/Time: 2015-11-05 13:06:20.008 +1100
OS Version: Mac OS X 10.9.5 (13F1134)
Report Version: 11
Anonymous UUID: 91C0E73D-500C-7D1D-B74D-41B671EFE1AE
Crashed Thread: 0
Exception Type: EXC_CRASH (Code Signature Invalid)
Exception Codes: 0x0000000000000000, 0x0000000000000000
kernel messages:
VM Regions Near 0x7fff724350a8 (cr2):
__LINKEDIT 00007fff6d8b0000-00007fff6d8c4000 [ 80K] r--/rwx SM=COW /usr/lib/dyld
--> Submap 00007fff70000000-00007fff80000000 [256.0M] r--/rwx SM=PRV process-only VM submap
unused shlib __DATA 00007fff70232000-00007fff72a9d000 [ 40.4M] rw-/rw- SM=COW system shared lib __DATA not used by this process
Thread 0 Crashed:
0 dyld 0x00007fff6d83e028 _dyld_start + 0
Thread 0 crashed with X86 Thread State (64-bit):
rax: 0x000000000000000d rbx: 0x0000000000000000 rcx: 0x0000000000000000 rdx: 0x0000000000000000
rdi: 0x0000000000000000 rsi: 0x0000000000000000 rbp: 0x0000000000000000 rsp: 0x00007fff57ba6d00
r8: 0x0000000000000000 r9: 0x0000000000000000 r10: 0x0000000000000000 r11: 0x0000000000000000
r12: 0x0000000000000000 r13: 0x0000000000000000 r14: 0x0000000000000000 r15: 0x0000000000000000
rip: 0x00007fff6d83e028 rfl: 0x0000000000000201 cr2: 0x00007fff724350a8
Logical CPU: 0
Error Code: 0x020000f4
Trap Number: 133
Binary Images:
0x7fff6d83d000 - 0x7fff6d870817 dyld (???) <7AD43B9B-5CEA-3C7E-9836-A06909F9CA56> /usr/lib/dyld
External Modification Summary:
Calls made by other processes targeting this process:
task_for_pid: 0
thread_create: 0
thread_set_state: 0
Calls made by this process:
task_for_pid: 0
thread_create: 0
thread_set_state: 0
Calls made by all processes on this machine:
task_for_pid: 1140
thread_create: 0
thread_set_state: 0
VM Region Summary:
ReadOnly portion of Libraries: Total=288K resident=280K(97%) swapped_out_or_unallocated=8K(3%)
Writable regions: Total=8444K written=0K(0%) resident=12K(0%) swapped_out=0K(0%) unallocated=8432K(100%)
REGION TYPE VIRTUAL
=========== =======
STACK GUARD 56.0M
Stack 8192K
VM_ALLOCATE 8K
VM_ALLOCATE (reserved) 4K reserved VM address space (unallocated)
__DATA 252K
__LINKEDIT 80K
__TEXT 208K
mapped file 240K
shared memory 4K
=========== =======
TOTAL 64.8M
TOTAL, minus reserved VM space 64.8M
Model: MacBookAir6,2, BootROM MBA61.0099.B20, 2 processors, Intel Core i5, 1.4 GHz, 4 GB, SMC 2.13f15
Graphics: Intel HD Graphics 5000, Intel HD Graphics 5000, Built-In
Memory Module: BANK 0/DIMM0, 2 GB, DDR3, 1600 MHz, 0x80AD, 0x483943434E4E4E384A544D4C41522D4E544D
Memory Module: BANK 1/DIMM0, 2 GB, DDR3, 1600 MHz, 0x80AD, 0x483943434E4E4E384A544D4C41522D4E544D
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x117), Broadcom BCM43xx 1.0 (6.30.223.154.65)
Bluetooth: Version 5.2.7f4 15858, 3 services, 23 devices, 1 incoming serial ports
Network Service: Wi-Fi, AirPort, en0
Serial ATA Device: APPLE SSD SD0256F, 251 GB
USB Device: Internal Memory Card Reader
USB Device: Z Mate 8GB
USB Device: BRCM20702 Hub
USB Device: Bluetooth USB Host Controller
Thunderbolt Bus: MacBook Air, Apple Inc., 23.6