Bluetooth Code 43 concerns the adapter or device that Windows stopped. Confirm the exact Device Manager entry before reinstalling any driver.
Protect your files first
Back up important files when possible. If the drive is encrypted, locate the BitLocker recovery key before recovery changes. Stop if storage appears to be failing or this is a work or school managed PC.
What to record
Adapter model, PC model, Windows build, connected devices, and the last driver change.
The exact message, Windows version, and whether the desktop still opens matter more than a guess based on the symptom name.
Try these safer checks
Check whether the adapter is enabled and compare the OEM driver for the precise hardware. If a recent update preceded the error, review the supported rollback option.
Change one thing at a time. After each check, see whether the same symptom returns and write down what changed.
When to stop and get help
Avoid generic driver-download sites and changes to managed PC policies.
If this is a work or school device, contact its administrator before changing managed settings.
Keep track of your checks
This checklist stays in this browser session. It is not sent to WinErrors.