If your display is not showing a picture with the 8K Ultra High Speed HDMI Cable (ST-8KHC2MM), the usual causes are a loose connector, the wrong input selected on the display, or hardware on one end that cannot handle the resolution you are asking for. The 8K Ultra High Speed HDMI Cable is backward compatible and supports 5K, 4K, 1440p, and 1080p in addition to 8K, so it should give you a picture on almost any HDMI display once everything is connected correctly.

How to fix display problems with the 8K Ultra High Speed HDMI Cable

1. Reseat both ends of the 8K Ultra High Speed HDMI Cable. Align each connector before inserting it and do not force it into the port.
2. Switch your TV or monitor to the HDMI input you actually plugged into. Most displays have several HDMI ports and will show nothing until the matching input is selected.
3. Try a different HDMI port on the display. On many TVs only one or two ports carry the highest bandwidth.
4. Detect the display on your computer. On a Mac, open System Settings and go to Displays. On Windows, open Settings, go to System, then Display, and select Detect.
5. Drop the resolution to 4K at 60Hz as a test. If the picture appears at 4K, the cable and connection are fine and the original setting was more than one end of your setup could handle.
6. Check what your hardware supports before expecting 8K. To get 8K, your host device needs an HDMI 2.1 port and an 8K-capable graphics processor, and your monitor or TV must support 8K. If either end does not support 8K, the picture drops to the highest resolution both devices share.
7. If you are on a Mac, expect 4K at 60Hz. Because of a macOS limit, Mac computers output 4K at 60Hz over HDMI no matter what the display supports. Macs only reach 5K or 6K through Thunderbolt.
8. If you are running the 8K Ultra High Speed HDMI Cable through a Type-C to HDMI adapter, the maximum is also 4K at 60Hz, regardless of your display.
9. Swap in a different HDMI cable, or test the 8K Ultra High Speed HDMI Cable on a different HDMI display, to work out whether the cable, the source, or the display is the problem.
10. Inspect the cable jacket and both connectors for fraying, kinks, or bent pins. Do not use the 8K Ultra High Speed HDMI Cable if the cable or connectors are damaged.
11. If you have picture but no sound, check whether your TV or AV receiver supports enhanced Audio Return Channel (eARC), then test the same audio path with another source to confirm where the issue is.