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This page contains general troubleshooting questions and answers. For troubleshooting specifically in Python or MATLAB, see the relevant subpages.

VPixx hardware is plugged in and powered on, but is not detected by software

If you recently crashed out of an experiment program, your VPixx Device Server may have frozen. You can restart it via the following methods:

  • Windows:

    • Search for the “services” application in the menu, and open it (should have a gear icon)

    • Scroll down the list of services to “VPixx Device Server”, right click this and select “restart”

  • Mac:

    • Open a terminal and enter:

sudo launchctl stop com.vpixx.deviceserver
sudo launchctl start com.vpixx.deviceserver

  • Linux:

    • Open a terminal and enter

sudo systemctl restart vpixx-device-server

If this does not resolve the issue, please contact technical support (

Console display (video out 2) shows an “Out of Range” error

If the console monitor is a make and model recommended by the VPixx team, or if it was purchased directly from us, this error is normal and should disappear on its own after about a minute. After this your screen will work normally.

If the message persists for several minutes, or is accompanied by other screen artefacts (like tearing or flickering), your monitor may not be suitable for use as a console. Please ensure it is set to 1920 x 1080 @ 120 Hz. If this does not resolve the issue, you may need to use a different monitor.

VPixx hardware is detected, but video is not showing or is showing poor quality video

You may be sending video at an unsupported resolution or refresh rate. Check your graphics card and display settings and make sure they are set to one of our specified resolutions and refresh rates. Please also ensure your video cable is dual-link DVI, not single-link.

In some cases you may also need to specify your display EDID. The EDID is a setting on your display hardware that indicates to the graphics card the preferred resolution and refresh rate of the display.

If your desired resolution does not appear in your display settings, you can specify the display EDID in PyPixx in the Configuration widget. There are two ‘slots’ available, which you can set to two of your preferred settings. You may need to restart your VPixx device for the new EDIDs to take effect.

PROPixx image is flickering

This is typically a sign that your video signal is being attenuated. This is common with longer cables. If you have a booster (small box connected to the video cable, located near the projector), you can try adjusting the dial on the side until you achieve a stable image. If you do NOT have a booster, you may want to try a different, shorter video cable.

VIEWPixx monitor has a flashing red square in the top corner

The flashing red square in the top corner of the display indicates that your video frame rate has dropped below 100 Hz (usually to 60 Hz). When this happens, the VIEWPixx goes into “resampling” mode and repeats incoming video frames in order to continue displaying images at a rate of 120 Hz.

Resampling mode can cause problems for timing-sensitive experiments; the red square is a warning that is a bad idea to collect data while the display is behaving this way.

You can resolve the issue by changing your display settings such that the VIEWPixx is showing full HD (1920 x 1080) at 120 Hz. You can usually change this in your display settings.

If you don’t see an option for 1920 x 1080 @ 120 Hz, it may be that you are using a single-link DVI cable, not dual-link. In that case you may need to swap cables and restart the monitor to be able to change the display settings.

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