Too many problems with the upgrade on my Windows 7 system and as I built (and upgraded a couple of times) it in 2008, I went ahead and built a new system.
Computer Case: Thermaltake LEVEL 10 GT, White
Power Supply: EVGA Supernova 850 watt G2 80 Plus Gold
Motherboard: Asus Maximus VIII Hero
CPU: Intel 4 Core i7-6700K
CPU Cooler: Corsair H90 (Hydro 90; Water based cooler)
Memory: G.Skill Ripjaws V Series DDR4 PC2666 (4x8G: 32GB)
Video: MSI GTX 970 Gaming 4G (2x)
Storage: Samsung 850 EVO (500GB SSD) (Boot disk)
Storage: Seagate 2TB Internal Desktop Hard Drive- 3.5" Form Factor, SATA III 6 Gb/s, 64 MB Cache (x2)
Monitor: Wasabi Mango UHD430 Real 4K HDMI 2.0 SE 43 LG AH-IPS Panel UHD 3840×2160 Displayport 1.2 43-Inch 10Bit Monitor
Monitor: Acer G235H (2x)
Keyboard: IBM Model M (1986)
Mouse: Logitech Wireless Trackball M570
WebCam: Logitech WebCam Pro 9000
Speakers: Logitech X-540
OS: Microsoft Windows 10 Pro
Blu-Ray: LG Black Blu-ray Disc Drive SATA Model UH12NS30
The main issue is the sound buzzes if something plays that is running in shared space such as YouTube, iTunes, or the Windows Video Player. The buzzing coincides with the system pausing as if the issue is taking full control of the system. In games that take over control of the sound, no buzzing.
I checked out the 'net and tried pretty much everything suggested with no success. But everything seemed to point to the Realtec on board sound. My old system had a Soundblaster X-Fi which had problems with the Windows 10 upgrade from Windows 7. Realtec points to the motherboard vendor for drivers and the Republic of Gamers folks seem to keep the system updated pretty often.
I'll also note that the 5.1 sound system doesn't work either. Just two speakers function regardless of the setting.
Finally I sprung for a SoundBlaster X card. I installed it and the drivers and voices sound muted but music is clear. Then I updated to the drivers from last week and it reversed. Voices are clear but music is muted. I even disabled the Realtec on board sound at the BIOS. No change.
Eventually I simply disabled the SoundBlaster card, enabled the Realtec, and at least games work.
With the Windows Anniversary download that just was installed, now there's buzzing and the pause in games which now kills the experience.
I'm going to poke at the drivers a bit more and then maybe roll back and maybe roll all the way back to Windows 7 on the new system.