How to Fix the Windows 11 Installation Crash on SSD using WinToUSB

If your Windows 11 installation using WinToUSB or EasyUEFI crashes with a blue screen referencing fltmgr.sys or INACCESSIBLE_BOOT_DEVICE, you’re not alone. This issue typically appears when trying to install Windows to an SSD using a virtual disk (VHD/VHDX) setup. The core problem lies in how the bootloader is created and how the system interacts with UEFI and Secure Boot.

This happens because either the wrong installation mode is used or the BIOS/UEFI settings aren’t properly configured. Here’s how to fix it and get a fully working Windows install without the crash.

Also read: Zoom Not Responding on Windows 10 – Step-by-Step Fixes

Steps to fix the Windows 11 Installation Crash error:

1. Install the WinToUSB software from the official webpage on your Windows machine.

2. Open WinToUSB and choose your Windows ISO (Windows 11 or 10).

3. Next, select Installation Mode to Legacy (not VHD or VHDX)

4. Choose your target SSD and set the Partition Scheme to GPT for UEFI

5. Then, boot into BIOS/UEFI mode and set Boot Mode as UEFI.

6. Disable Secure Boot and set your SSD as the first boot device

7. Restart your PC, and voila, you are free from the WinToUSb 77% error

Note: While this method worked for most users, there may be a chance it might not solve the error for you. Don’t hesitate to get in touch with Microsoft support to resolve if required.