installing windows 11

Question

error message: You can't install on a flash drive using Setup

Answer 1

Hi,

To resolve the error "You can't install Windows on a USB flash drive using Set-up", please do the following:

1] Create a System Restore Point.

2] Press Win + R, type regedit.exeand press Enter. This opens the Registry Editor. In the Registry Editor, go to the following branch:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control

In the right pane, rename the value PortableOperatingSystem to PortableOperatingSystem.Old.

Exit the Registry Editor and restart Windows.

Answer 2

Please try these steps:

Open Registry editor.

Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control.

Set PortableOperatingSystem named registry DWORD to 0.

Try upgrading again.

P.S. If you're new to registry, create a System Restore point first before try above steps.

Answer 3

The message appears because Windows Setup running inside Windows does not support installing Windows directly to a USB/flash drive. To proceed, install Windows 11 to an internal disk, or use the USB only as bootable installation media, not as the target drive.

To use a USB flash drive correctly in this scenario:

1. Prepare the USB as installation media
   1. On a working Windows PC (technician PC), connect a USB flash drive with at least 5 GB free.
   2. Open Disk Management (right‑click Start > Disk Management).
   3. Format the USB partition as FAT32 and then mark the partition Active.
   4. Copy the contents of the Windows 11 ISO/DVD to the USB drive.
      • If the install.wim file is larger than 4 GB, copy all other files first and then split install.wim using DISM as shown in the reference.
2. Boot from the USB and install to an internal drive
   1. Insert the prepared USB into the target PC.
   2. Power on and use the boot menu key (for example Esc/F10/F12) to boot from the USB.
   3. In Windows Setup, choose Custom installation and select an internal disk (SSD/HDD) as the destination. Do not select the USB drive.
   4. Complete setup and remove the USB when prompted.

Windows 11 cannot be installed and run from a standard removable flash drive using normal Setup; the USB’s supported role here is as bootable installation media only.

---

References:

• Install Windows from a Flash Drive