Volume controls not working

yea it's frustrating - i've been direct messaging comcast back and forth - they will now get me in touch with ab "advanced repair team to look into this further"

Sorry to hear that. I did a refresh/reset of my box yesterday and it's been about 18 hours and holding. But this has happened before. Then all of the sudden it will start again for no reason. Only way to get it back is to turn TV/Box off and on again. Sometime 3 or 4 times are needed. 

I would be interested in knowing how that plays out. I was messaging them as well. They only came up with replacing remote as well as replacing DVR box and doing system reset. I will contact them after I replace the remote and see what they say. 

I might add yesterday I reset box 2 or 3 times while going back and forth with messaging. So far it has held. Hopefully something "stuck" and will continue. 

this seems to be a samsung tv issue not comcast - i tried everything from resetting everything and getting new boxes - then i went to the samsung forums anfd found this fix:

I've had the same issue and tried everything listed in these forums.

I've read: 

1. New batteries in the remote

2. Power cycle the TV

3. Reset the audio

4. Reset the TV to factory default

5. Remove batteries from remote, hold power button for 10 seconds

6. Remove batteries from remote, hold power button for 40-50 seconds

7. Hold the 'down' arrow and 'pause buttons simultaneously until a message displays "remote learned"

None of these worked! After troubleshooting and using my process of elimination, I discovered disabling 'Autorun Smart Features' solved my problem! 

Did you have to redownload Apps?

I reset and refreshed a couple of times 4 days ago. Also paired remote.  Several times. Changed my sound output from Bitstream to PCM(read that somewhere). New remote acquired X15. So far after 4 days sound is working. 

Thanks. I see reset smart hub. Nothing to disable auto run. 

thanks for that. Where did you find that option?

support> self diagnostics > reset smart hub

good info for the X15 remote; but what about the equivalent for X11 remote?

AJO83

What issues are you having?

XR11 remote - volume will not go above a certain level.  Tried unpair/reprogram remote.   Samsung TV.  Looks like a Reset Smart Hub would require me to reload all apps, reestablish all saved login/passwords, browser bookmarks, etc. Not something I would want to do so....  I did run the Samsung Sound Test and the Samsung remote raised and lowered volume perfectly.  When I exited the Samsung menu the sound stayed at the level set - UNTIL I touched the xfinity remote and then the volume limit occurs again.  Any ideas on how to resolve is appreciated!

Reset Smart Hub does not fix problems and is a pain to do.
Go into the apps screen on the Samsung TV. Look at top right corner is see what % of memory it shows. In my case it was 0%. I off loaded a bunch of garbage apps and now I’m at 19% memory. The no memory reeks havoc somehow. PROBLEM SOLVED. It’s been 3 weeks and no problems since. Shame on Samsung for not identifying a problem with this. It s not an Xfinity issue

Received new set top box today with remote and after about 2 hours, customer service is sending a replacement remote.  Will not pair with my LG tv so that the remote will control volume/mute......all other controls work fine!  Grrrrr

Update.....returning set top box and using the old one.....going with a Roku stick to access Disney+ and Apple+TV.  What a waste of 3 hours trying to install.