can't select 5.1 uncompressed for HDMI audio

That's simply incorrect. The Xbox One has output surround sound since its release-- DTS and 5.1/7.1 uncompressed multichannel PCM over HDMI. Until the last update, it did not support outputting a compressed Dolby Digital bitstream, which is what is needed
for optical (because optical can't carry uncompressed 5.1/7.1). It does now, however.

OP, it sounds like you are selecting 5.1/7.1 uncompressed, which is not supported by TVs (that is for a receiver (AVR))--and that is why you can't select it when HDMI is set to Auto. Most likely your TV is just seeing it as 2.0 (stereo) audio. You need
to set the Xbox One audio to bitstream with Dolby Digital encoding. Even then, please be aware that very few TVs pass DD 5.1 from an HDMI source out though the optical out. What you may end up getting is virtual surround sound, not true discrete 5.1.

It does or at least the next update does.

Settings-->Display & sound:

- Digital Audio:

1. HDMI audio (stereo uncompressed, 5.1 uncompressed, 7.1 uncompressed, Bitstream out)

2. Optical audio (Off, Stereo uncompressed, Bitstream out)

-if u select Bitstream out (DTS Digital Surround, Dobly Digital)

Hi, one more thing , as sson as i am selecting 5.1 uncompressed in hdmi audio section and going back, then checking again and it is reseting automatically to stereo uncompressed, any solution for this ?

Is that something that my headphones connected to console doesnt support 5.1/7.1 ?

Here's an interesting update. On a whim, I tried disabling HDMI Auto Detect and instead manually selected HDMI and 1080p.

Before, I would just get an error to check my audio receiver. Now I can actually select HDMI 5.1 Uncompressed. I get audio with that setting. I can also select Bitstream Out now, which I couldn't before, but there's no audio, just silence.

Gunjee, you must connect your soundbar to an optical (or red/white analog) audio OUTPUT on your TV, NOT an input as you described.

OrphenCB, you can't select the 5.1/7.1 uncompressed audio options because your setup doesn't support it. Optical out only supports 2-channel uncompressed PCM or compressed DD 5.1 (which Xbox One currently does not support). You also can't send uncompressed
5.1/7.1 PCM to your TV via HDMI because your TV doesn't support that, which the Xbox knows via the HDMI handshake and, thus, disables. Try setting the Xbox to send DTS over its optical out to the receiver if your receiver supports DTS. Otherwise, you'll have
to wait until the Xbox can output DD or get a better/newer receiver... BTW, if/when the Xbox supports DD output over optical, run that directly to your receiver--not via HDMI to your TV then optical out to your receiver. Most TVs will NOT send DD 5.1 from
an HDMI source out via the TV's optical out.