You need to make sure the files you have on the usb has resolution no higher than 24b/192 kHz if they are PCM. If the 7012 can't play, then I doubt the 6700 is defective. It would has to be something you were doing. Did you try playing the same files on the network, that is, directly from your PC?I can use some help. Can any 6700 owner's here check for the function of their front USB input. I posted the following on AVS Forum, but have not yet got any reply.
"I just got my new Denon AVR-X6700H from Visions on Monday. I wanted to get front wide's and more Auro 3d up-mixer channels for my home theater. I took out my Marantz SR-7012 which has been in that position for 5 years. I have a 7.2.4 system with JVC 590 projector and 138" Elite screen.
The 6700 sounds good and seemed to work well until I checked out one feature this evening. The front USB port does not seem to work. I have some FLAC files (8 albums from HDtracks). I have them on several USB sticks including Kingston and Lexar. I have always had no issue playing these through the USB inputs on my Yamaha RX-3070/3050, Panasonic 900/820, and my Oppo 103/203's.
I plugged my USB stick into the 6700 and it basically is all messed up. It can freeze the whole receiver up or turn the tv picture into distorted lines. It may also play some of the song with a bunch of skips every several seconds. I was not sure if the unit was defective or what. I tried all of these USB's in all of the units mentioned above and they work perfectly as they normally do.
I then took these same USB sticks up to my living room system where my SR-7012 now is being used. I know that I have used all of these USB sticks with the Marantz and they always worked without issue. Surprisingly I was getting the same behaviour from the Marantz........could not play at all from the menu, freezing onscreen menu and the display on the Marantz was just flailing away displaying long sequences of numbers??
This seems to indicate that the 6700 may not be defective and that possibly a recent Denon/ Marantz firmware update has messed up the USB input. Both my 6700 and 7012 have the most up to date firmware. I am in Canada. I also checked these drives and they were formatted in fat32. I formatted a different USB drive in NTFS and copied some of these FLAC files from the original source and ............ same results....plays on everything accept the 6700 and 7012.
Can anybody chime in on this?
I had it on wi-fi, then I have also tried wired ethernet.......no difference. I wanted to find out if anyone that has a 6700, and the up to date firmware, has issues playing their flac via the front USB input. It seems very suspect that BOTH my 6700 and 7012 (which used to function normally) are both having a similar issue.
I also saw some of the firmware update logs and Denon seems to have been trying to fix USB file playback issues.
support.denon.com/app/answers/detail/a_id/3832/~/latest-heos-app-and-firmware-update-available
I know I fully updated the firmware of the new 6700 the day I got it and have also done recent updates on the 7012.
If I don't find out that other people are having the same issue......then my 6700 is likely defective and will have to go back. I hope this is not true because the discount on the unit was historic......even better than some pre Clamid-69 (Covid 19) era deals."