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Q When I’m streaming 4K through my Roku Ultra, I occasionally get an onscreen warning that says “not 4K-compatible.” The sources I use for streaming are HBO Max, Amazon Prime, and Netflix. I don’t subscribe to Netflix 4K but I get the message there too. It doesn’t make any sense to me. I’m using 4K-capable AudioQuest cables and my gear is an Emotiva RMC-1L A/V processor, Roku Ultra, and an 85-inch 4K Sony Bravia LCD TV that supports HDCP2.2. I also have a Panasonic DP-UB9000 Ultra HD Blu-ray player but there’s no issue with it. Every check I make shows that I am set up properly for 4K streaming and my Wi-Fi signal to the Roku is great. Any ideas? It’s making me crazy. —Michael Henn, via email

A Start with some basic troubleshooting to see if you can narrow down the problem. First, disconnect everything and run the Roku directly to the TV. With the Sony TV, you’ll also want to make sure the HDMI Signal Format for the input you’re using is set to “Enhanced” format, an option that might only be available on certain inputs, like HDMI 3. Then reconnect the Roku to your Emotiva processor and try different HDMI inputs; HDMI inputs vary in circuit-path design and some are more reliable than others. You can also try different HDMI cables but make sure they are at least 3 meters (9 feet) in length. Shorter cables can pose issues with some components.

Having said all that, Brent thinks the most likely cause is related to HDMI “Hot Plug Detection.” Just unplug the HDMI cable from the Roku and plug it back in to reset the hot-plug. If that solves the problem, Metra makes a device called the HDM-AIO2 ($180 at Crutchfield) that forces a hot-plug reset. It does require a relay to trigger it, and Metra offers the CS-IRKITCCUS ($80 at Crutchfield) with a built-in double-throw relay that will do the trick.

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