Hi All, just want to share that this issue happened to me as well yesterday night.
Using Win 7 ultimate i7 6700k rig.
I was trying to change my sound output from my speaker to Corsair void wireless via the sound notification when I noticed that void rgb was not available for me to select. The LED on the ear cup was also not on.
I have tried to on/off the headset and the dongle appeared to have paired whenever I on the headset but there wasn't any sound or device found under the sound notification.
Opening CUE shows no device detected.
I proceed to upgrade the CUE firmware which resulted the same. Then I uninstalled and reinstalled CUE but to no avail was the device detected.
Note: without any device detected even with the headset charging cable plug into one of the USB port. there is no way to force firmware install {method on getting out of bootloader mode -which I believed to be the issue I had}.
After googling for a bit, a method was found:)
I simply change the USB port I used for the dongle and the device was able to be detected for me use the headset.
"TLDR" - you may want to try change to another USB port to see if that helps if your headset suddenly fail to on.
But I am kinda disappointed that such bug happened all of a sudden after using the headset for like 1 month plus without much issue - other than the auto shut down bug which I had rectified via the app data file.