CSR 4.0 Dongle driver problem - Microsoft Community
https://answers.microsoft.com/en-us/windows/forum/all/csr-40-dongle-driver-problem/04a67f98-415b-48e7-a933-ae37514201ff
-Windows+X> task manager> bluetooth, right click on all drivers, Uninstall. Restart the PC. -Let Windows reinstall all generic sound drivers: Windows +X, Device Manager, under Sound Controllers, right click on all drivers, Uninstall. Under Audio Inputs and Outputs, right click on all Drivers, Uninstall. Restart the PC.
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