FiiO SW not running on Windows 10? - You might be missing a specific version of Microsoft's .NET 3.5 on your PC.
Long Time Head-Fi reader, but new as a poster.
Just thought I'd pass on some advice as I ran into this when updating my Firmware on both a Q5 and Q5s using Windows 10 ver. 1803 or newer
I've seen questions about FiiO's installers and Windows 10 (quite a bit earlier in this thread, and other FiiO threads) and wanted to pass on this info.
Coming from the PC industry, I recognized the error when I got it, as the cryptic typical MS error box for .Net
Newer Versions of Windows 10 do NOT have the older versions of .Net by default (it only loads version 3.54 and 4.x, which are supposed to be 100% backwards compatible...They are not)
Don't want to clutter up Head-Fi with the process to load older versions of .Net, as it is well documented on the various Microsoft/Win 10 forums out there.
But if your having this problem, look to load Microsoft .Net 3.5 and .Net 3.52 as it appears the base code for the FiiO installer is looking for those older versions of Microsoft's .Net 3.5
You can have all of the older versions of .Net running along side the latest 3.5x releases.
Once I loaded the older versions of .Net regardless of the version of Win 10 ( worked on my and friends PC's who also use FiiO products) the updaters and installers ran fine and properly updated the Firmware.
CAUTION: Just make sure you go back and run the Microsoft Windows Update tool to insure you get ALL the patches for the older versions of .Net 3.5x as there are some NASTY exploits and viruses that are looking for the older unpatched versions of .Net
Hope this helps someone on this forum