Solved Windows caching USB drive, even after reboots.

I have a very odd issue here...

I have a USB drive (actually a Raspberry Pi Pico 2) where the filesystem is not behaving as expected. I updated some code on the Pico 2, ejected the drive letter (K:), unplugged the cable, re-plugged the cable and now the filesystem seems "stuck". If I try to create a file, I get an unexpected error... Error 0x8000FFFF: Catastrophic failure.

I reboot my system and see the same issue. I assume a corrupted file system, so I wiped the flash memory successfully. I reinstall firmware, that I freshly downloaded from the internet, and my code is back on the drive, and I'm getting the same error. It looks like nothing was wiped.

So I assume that the Pico 2 has a hardware failure. I shut down the system and replace the Pico 2 with a brand new one. I boot back into Windows and... My old files are *STILL* there on the USB drive. That is impossible as the old Pico 2 is not physically connected to the computer and thew new Pico 2 has never been plugged into a PC before.

Why do I think that this is a Windows issue? I shut down my PC and booted into Mint Linux. Both Pico 2 drives work normally. No issues whatsoever. I reboot into Windows and the issue returns. I still see the old files and can't write to the filesystem.

Thinking that this is a device issue. I unplug the Pico2. Then I go to device manager and show hidden devices. I uninstall every Pico 2 that I can find. Reboot the PC and then plug in the Pico 2... Same issue.

Where would Windows be caching this outdated drive information and how can I correct this?

Can you disconnect all usb devices and if the Linux system is on a separate drive,then disconnect it.The intention is to only have Win 11 available.
If so,then restart the PC and in Task Manager>Startup,disable all third party programmes from autostart.
In Terminal [admin] type in---dism /online /cleanup-image /restorehealth ---and run it.
Next type in ---sfc /scannow ---and run it until a clean report is given.
Reintroduce the drive and usb devices ONE at a time to identify which one,if any ,caused the problem.

Just to test further. I opened a Windows 10 VM on my Windows 11 PC. I connected the Pico 2 USB device to the VM and the devices came up in the Device Manager. I was able to edit the code.py file without any issues. I shut down the VM and let the Pico 2 connect back to the host and it's won't let me write do the Pico 2 disk again.

This rules out any hardware issues on the USB side of things.

There must be something corrupted in my Windows 11 system... no idea what it could be.

What I've tried:
- Deleting all the Pico 2 devices from device manager, including hidden ones
- Changing the drive letter used my the Pico 2
- Tested fine on Mint Linux
- Tested fine on another Windows PC
- Tested fine on a Windows 10 VM on the same PC that is having problems.

I tried out the Device Cleanup Tool found here: Tools for Windows and it seems to have helped some. The Pico 2 still has issues occasionally, but I can work around them and get it back to normal.

I think the issue is that I am trying to use the Pico2 to be a HID keyboard and gaming device and I'm not setting the descriptors properly... or there is an issue with the CircuitPython modules that I am using.

This is a really strange issue! It sounds like Windows is holding onto cached drive letter assignments in the registry even after the physical device has changed. Here are some things to try:

1. **Clear the USB storage driver cache** - Open Device Manager, go to View > Show hidden devices. Expand "Disk drives" and look for any grayed-out entries (your old Pico 2). Right-click and uninstall them, checking "Delete the driver software" if the option appears.

2. **Remove mountpoint registry entries** - Open Registry Editor and navigate to:
`HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices`

Look for entries related to K: drive and delete them (backup first!). This forces Windows to rebuild the drive letter associations from scratch.

3. **Try USBDeview** - This free utility from NirSoft can show you all USB devices that have ever been connected. You can remove ghost entries that Windows is still tracking.

4. **Assign a different drive letter** - Try manually assigning a different letter to your new Pico 2 in Disk Management to see if the issue follows the letter or the device.

The fact that it works fine in Linux confirms this is definitely a Windows caching issue rather than hardware.

It was the USB descriptors I was using on the Pico. Now that I have proper descriptors I haven't had any issues.