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Any time the headset loses tracking or is taken off your head, the VIVE Space Calibrator play space alignment will drift. Ensure your room is well-lit and that you have set the Meta Quest headset sleep time to Never in the power settings menu of Horizon OS in the headset Settings → System → Power → Sleep mode → 4 hours or never in the Quest headset’s Horizon OS settings.
Useful Resources
VIVE Ultimate Tracker PCVR Beta Troubleshooting FAQ (Discord link)
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