Audio File Loading Slowly / Dropouts

[David A]

Roon is connected to the internet via Wi-Fi.
Local files are either being fed directly to Devialet via USB, or from NUC to Berkeley Alpha to Devialet via AES/EUB. (I have tried both with the same results)
No files are fed to the Devialet over a network connection.
Roon works fine disconnected from Devialet.
I get error message only when connected (hardwired) to Devialet.

Having had various digital equipment over the years I have found that it is usually some silly setting on one or two pieces that finally gets everything to play nicely together.

 What do you mean when you say "Roon works fine disconnected from Devialet"? What else is connected to Roon and how are those devices connected to Roon?

You've also detailed 2 different connection methods to the Devialet, a direct USB connection from the NUC and a NUC to Berkeley Alpha via USB/Berkeley Alpha to Devialet via AES. Do you get the error message regardless of which of those connections you are using or with only with one of those connections and, if so, which one?

As I said earlier, the only reports of this problem with Roon and a Devialet relate to streaming over a gigabit ethernet connection using Roon's own RAAT protocol. That strongly suggests your problem is not related to the Devialet and has to be related to the only network connection Roon is using which is the connection between Roon and the internet. Based on what you've said, that's the connection I would be looking at and for information and advice about that connection I would start with the link in the post from @daniel.avasilichioaei above. If you can't solve the problem with the information in that link then I would suggest contacting Roon support or posting a message on Roon's own forum because it does not appear that the problem is related to your Devialet.