​In some case even the new driver has problem on Windows 10 64 bit. I haven't tried to re-enable secure boot on my system after the update to Winows 10 anniversary edition but with previous insider builds Windows won't load the driver if I don't disable secure boot and was reporting error 52

Have you tried to disable secure boot in your BIOS settings?

​You should try to disable secure boot option in the BIOS

The solution above works only in Windows 7, on Windows 10 insider build there's probably some problem that have to be fixed by Microsoft before releasing the anniversary update as I have the same error 52 also from the last AMD display driver

Do you have any news about the compatibility problem with the X3 II? I think FiiO is still looking at the issue 

I know it but there are some problems with X3 II, FiiO has made a specific firmware update  v.1.6 to fix the compatibility issue with the new DAC driver but it didn't fix the problem for me.

Is there anyone using FiiO X3 II with last DAC driver on Windows 10?  On my notebook Windows won't load the drivers reporting error 52. I have to disable secure boot or boot every time with device driver signature verification disabled.  I'm running Windows 10 last insider build.   

I'm running Windows 10 x64 last insider build (build 14316 at the moment). I have problems only with FiiO DAC driver, all other drivers installation went just fine for both WHQL and not WHQL drivers.  Btw at the moment I've disabled the secure boot as in any case the fast startup function...

Same thing also with new fw 1.6 that should have fix the issue, I still get error 52  stating that "Authentication code signature is not valid" 

With secure boot disabled installation of the unmodified drivers with new fw 1.44 beta (DAC) went fine but still can't use the FiiO X3 II if secure boot is enabled

Thank you so much, I 'll try as soon as I have some free time!  

When it has been released? I haven't saw it on the official forum. So it was a fw problem not related to the drivers?

Hi! You have two choice as the old driver v1.61 has been removed from FiiO website: 1) You can wait until FiiO will release the new driver v3.34 also for X3 II as it has already been released for X3, X5, X5 II and X7, but they expecting some problems with X3 II driver signature verification...

You can install the new driver 3.34 also on the X3 II, extract the installer, open both the .inf files and replace the ID with those from the old driver.

FiiO has released the new DAC drivers for his product based on Thesycon last version 3.34. The new driver for the X3 II is not available at the moment due to a problem they're still working to fix. 

Can you modify this driver to support FiiO products? It seems it's based on Thesycon driver v3.29 http://www.resonessencelabs.com/resonessence-generic-thesycon-usb-audio-2-0/ Edit: I've modified the .inf files by myself, the drivers are working correctly both ASIO and WDM.

Try to manually install the driver. In the device manager select sound, video game controller, then open the action menu and select add legacy hardware, chose select the hardware from a list, select "sound, video game controller", locate the .inf file and select your model from the list at the...

Version 3.26 available http://www.thesycon.de/eng/usb_audiodriver.shtml 

Ok I did it. :D

I have the FiiO X3 2nd Gen. The installation went fine and everything works using ASIO in JRiver, but I can't see the audio device in Windows and the FiiO USB Audio Class 2.0 DAC driver has an error saying there's no available driver to install.