Hi, guys.
I am about to have a headache because of this error.
I have been so many searching, asking, trying in vain.
I just found this forum full with nice discussion and many problems solved,
and am posting new thread with hope.
Please understand if some expressions look odd or rude,
as English is not my mother tung and I wouldn't mean that.

Alright.
I have a bluetooth dongle. (Chipset seems CSR8510 A10)
And it worked very fine with basic drivers which is included in Windows 10.
I just plugged the dongle in my computer, and windows automatically searched and installed drivers,
and Bluetooth icon was on the system tray.
I remember that the names of drivers are Generic Bluetooth Adaptor or Radio.

One day, somehow my windows went bad - couldn't be booted.
So I took windows recovery to some past point.
After that, when I plugged the dongle in my computer,
windows tried to install drivers and failed with error message 'cannot find the file specified'.

I tried to install so many kinds of other third party drivers,
sfc/scannow, DISM-restorehealth... etc. in vain.

During that fail-full trial, I realized some structure of drivers.
C:\Windows\INF\bth.inf - this file seems the source install codes of bluetooth drivers.
If you just open this file with notepad, you can find so many codes.
It says copy files, add registry, and more things I cannot understand.

And if I right-click this file and select 'install',
error message 'cannot find the file specified' showed up as well.
But if I do the same thing in another PC with windows 10, no error and it works well.
With that PC, the dongle and drivers are installed well.
Then my guessing conclusion - direct install of bth.inf runs some procedure and seeks files 'specified',
and there might be some files missing.

If someone could understands the codes in bth.inf and teach me it seeks which files from where,
I might check those files and that will be the first step of solving.
This idea might be wrong, I'm just trying

Also, any suggestion, opinion, case experienced and every comments will be very thankful.