I apologize, now I'll add all the information.
ASUS Z-10 PRO GAMING
SAPPHIRE NITRO Radeon ™ RX 480 8G D5 OC
MONITOR ASUS VG 248 Displayport
RAM 32 GIGA
INTEL I7 6700K
WINDOWS 10 HOME 64 BIT
Functionally installed version: RADEON-SOFTWARE-CRIMSON-RELIVE-17.2.1
I also tried the 17.4.4 drivers, then I did other tests, such as installing only the video driver, or unplugging when installing on high definition audio, but the problem remains, the audio remains disabled.
I hope this description is fine.