Hello, I am a windows user and wish to create a multiboot usb which I can use to opt multiple OS to install but I am facing some problem, I used all types of software for making bootable usb like WINUSB, VENTOY and MULTIUSB but when I start the process after adding iso of windows 10 and windows 7, A blue screen of death appears and it says that a system service known as CLASSPNP.SYS has excepted and your pc needs to restart. I face this problem everytime while creating a bootable usb, I even tried this on another pc but this problem is still there, any help regarding this problem will be greatly appreciated.

After multiple failed attempts, I finally called Microsoft and asked. These are the instructions they emailed me:
1. Insert a USB at least 4GB in size
2. Open CMD prompt as Admin
3. Run diskpart
4. Run list disk
5. Select your flash drive by running "select disk"
6. Run clean by typing "clean"
7. Create a partition by typing "create partition primary"
8. Select the new partition by typing "select partition 1"
9. Format the partition by typing "format fs=ntfs quick"
10. Set the current partition as Active by typing "Active"
11. Exit diskpart

12. Mount your ISO. Use Virtual CloneDrive or something similar.
13. Navigate to the mounted image and install a bootsector. Ex. If the mounted ISO is on drive G: you'd navigate to G:\ boot and run:
C:\WindowsSystems32> G:
G:\> cd boot
G:\boot> bootsect.exe /nt60 E: (where E:\ in this case is my flash drive's letter)

14. Copy the entire contents of the ISO to your flash drive by typing " G:\> xcopy g:\*.* e:\ /E /H /F"

Once that's done, your USB is finished.

Bro these tricks are really helpful, I really appreciate your help

hasandurol said:

i need help .

Yes bro i also need help ,the above mentioned method is only for making a single boot drive using cmd but i need multiboot usb without classpnp.sys error

Is the SATA setting in the BIOS for the boot machine set to AHCI (which it should be) or something else? I haven't seen it set for something else in a while (multi maybe) but you could check that?

jackmeat said:

Is the SATA setting in the BIOS for the boot machine set to AHCI (which it should be) or something else? I haven't seen it set for something else in a while (multi maybe) but you could check that?

Bro what do you mean, actually i have upgraded my laptop with Acer ssd last year.

Manmeet_2008 said:

Bro what do you mean, actually i have upgraded my laptop with Acer ssd last year.

And please tell how to check the boot type

Bro, I checked the Bios and it was set to AHCI mode as you told. Now what to do.

Was just an idea of things I have seen. Have you tried different USBs of different sizes? And messed around with choosing ntfs/exfat/fat32? Pretty sure with windows installs now NTFS is preferred but could still try juggling around. Also, is it only with the Windows 10 isos on the multiboot USB? I know that the newer ISOs have had issues with being bootable and maybe they are the problem. Did you try with just a windows 7 ISO and maybe a ubuntu image as well just to see if those work. I personally use ventoy so trying things out like this is a breeze. I know I have had windows 10 isos that didn't work but they never crashed ventoy entirely so it seems something else is going on.

Yes bro You are right, It works if you first make the ventoy iso bootbable using rufus and then we should turn off the secure boot option in BIOS then we should boot into usb, then we should follow the steps of the ventoy live cd. After that the ventoy bootbable drive would be ready. Now I booted into windows and observed that there is no more space left on usb, then i used minitool partition software or any other software (minitool is recommended) and formatted the remaining exfat partition into NTFS or Fat32. After that the partition became visible and I copied both Iso files in that partition, in the end you can turn on secure boot . This should definitely work. You can install the ventoy iso from their github page.

Manmeet_2008 said:

https://github.com/ventoy/Ventoy/releases/download/v1.0.71/ventoy-1.0.71-livecd.iso

I am not sure why you are telling me how to use something I am already using for years without issue? I was just throwing some ideas at you to try. I know I never had to deal with using a separate partition tool to get the USB ready for ventoy at all. That was all part of the Ventoy2Disk.exe and I didn't mess with the livecd at all. Maybe whatever is causing you to be unable to use Ventoy2Disk.exe is also causing issues with the media creation.

Actually I was just telling how I solved the problem. Ventoy2Disk.exe is not working in my pc as when I start the process to make bootable usb , I get a BSOD and CLASSPNP.SYS exception error. Then I found the alternative of Ventoy2Disk.exe which is Livecd.iso

Manmeet_2008 said:

Actually I was just telling how I solved the problem. Ventoy2Disk.exe is not working in my pc as when I start the process to make bootable usb , I get a BSOD and CLASSPNP.SYS exception error. Then I found the alternative of Ventoy2Disk.exe which is Livecd.iso

Have you asked in the ventoy forums about this? I read this as a problem attempting to boot after creation, but this is a problem in actually creating the boot USB?

Bro I havent asked yet but will ask and tell you what they said

Manmeet_2008 said:

Hello, I am a windows user and wish to create a multiboot usb which I can use to opt multiple OS to install but I am facing some problem, I used all types of software for making bootable usb like WINUSB, VENTOY and MULTIUSB but when I start the process after adding iso of windows 10 and windows 7, A blue screen of death appears and it says that a system service known as CLASSPNP.SYS has excepted and your pc needs to restart. I face this problem everytime while creating a bootable usb, I even tried this on another pc but this problem is still there, any help regarding this problem will be greatly appreciated.

You'd probably want to keep it on fat32 for older computers and OSes, or ntfs for newer ones. Can't mix and match on the same stick. Then you'd need grub or some usb bootloader menu to input the other OS values.

Manmeet_2008 said:

Hello, I am a windows user and wish to create a multiboot usb which I can use to opt multiple OS to install but I am facing some problem, I used all types of software for making bootable usb like WINUSB, VENTOY and MULTIUSB but when I start the process after adding iso of windows 10 and windows 7, A blue screen of death appears and it says that a system service known as CLASSPNP.SYS has excepted and your pc needs to restart. I face this problem everytime while creating a bootable usb, I even tried this on another pc but this problem is still there, any help regarding this problem will be greatly appreciated.

U can use easy to boot to make a multi os bootable flash disk. it supports both legacy and UEFI systems.

Please help ....