Windows distinguishes between the two type of USB storage devices: Fixed or Removable.
Most USB FLASH drives are of the Removable type, but some are of the Fixed type (same as USB HDDs).
...

Easy2Boot v2 can now boot to UEFI32 and UEFI64 and SecureBoot UEFI64 and directly boot from ISOs in a similar way to Ventoy. It can still switch-in .imgPTN images too and MBR-boot as before.

You cannot copy a file greater than 4GB to a FAT32 partition. In your case this is a red herring.
I would suggest you make a bootable USB drive using the official Windows tool and download.
Just...

If you just want Windows-based payloads, WinSetupfromUSB should do the trick for Legacy and Secure UEFI-booting.
It just can't do Linux UEFI.

You can Secure Boot using FAT32+NTFS


Ptn: FAT32 - containing Win10 ISO contents EXCEPT \sources\install.wim or .esd and \sources\setup.exe
Ptn: NTFS - containing \sources\install.wim or .esd ...

You can try my Easy2Boot project instead of YUMI.
The supported ISOs are listed here List of tested ISOs\payloads (with instructions) :: Easy2Boot.
You just copy over the ISO files to the USB drive...

A user in Dubai says that he has a 'HaySenser' USB 3 external HDD enclosure and the drive appears as a Removable drive in Windows (e.g. he can run Easy2Boot and it works as a large Removable drive)....

If Easy2Boot is slow then get a faster USB drive!
Also try holding down the SHIFT key just as Easy2Boot starts to boot - this makes it load the fast USB 2.0 driver.

Well, not to get too 'off topic' but some 'fast' USB 3 flash drives are totally unusable at running WinToGo - e.g. Lexar P20 128GB USB 3. These types of USB 3 drives may have fast large-file transfer...

RMPrepUSB will show you whether the USB drive is Removable or not.
Usually all USB HDDs are of the Fixed type. I have never found one yet that is of the Removable type.
Most USB Flash drives are of...

set USBDRIVE=
FOR %%D IN (C D E F G H I J K L M N O P Q R S T U V W X Y Z) DO (DIR %%D:\USB.TAG > nul 2>&1 && (call set USBDRIVE=%%D:)
if "%USBDRIVE%"=="" echo ERROR: NO USB DRIVE FOUND & pause...

Thanks for letting me know:p

Yes. It should work. If the file copy goes OK and then it reboots from the internal HDD to start Win7 then it should work.
I don't understand why Rufus would install OK but not E2B.
What you could...

OK, but I don't quite understand.
You said the system was an old one, so it won't support UEFI will it?
Also, can you look at the contents of your win7 custom ISO - does it have any of these files...

P.S. Did you set the Boot Order in the BIOS to boot USB first, or did you set internal HDD boot first and then use pop-up boot selection menu (hit F key) to boot to USB drive? Hint: The second...

So Rufus installs OK on the same system and from the same USB drive, but E2B does not - is that correct? You did not mention that before!
BSOD is Blue Screen of Death - when Windows crashes you get...

Win 7 MS ISO does not normally contain UEFI boot files for USb booting. See http://www.easy2boot.com/add-payload-files/win7-uefi/
Is suspect your system is incompatible with the Win7 version you...

Hi
If you convert to .imgPTN then you can MBR boot (and UEFI-boot if you have EFI boot files in the image).
If Win7 installs OK but then fails on first boot from HDD, it sounds like something is...

Take a look at Easy2Boot and SDI_CHOCO feature. There is a YouTube video too.
http://www.easy2boot.com/add-payload-files/windows-install-isos/sdi-choco/

Hi,
I am the author of Easy2Boot. Over 1000 Easy2Boot USB drives are made every day.
If you have a specific problem, please give details.