Windows display scaling not at 100%
What it means
Your Windows display scaling isn't set to 100% — a known cause of a truncated or offset backglass on some cabs.
Why it happens
Windows applies scaling per user profile, often inherited from whichever monitor was primary when it was first set up, or changed silently by a Windows update.
How Pincab Toolbox detects it
The AppliedDPI value read from the registry doesn't correspond to 100% scaling.
Check your own pincab
Pincab Toolbox is a free Windows scanner for Visual Pinball X and PinUP Popper. It finds and explains problems like this one. No account, no telemetry.
Download for freeCovered: Visual Pinball X (10.x) and PinUP Popper. Not covered: Future Pinball, Pinball FX, Visual Pinball 9 and the other frontends (PinballX, PinballY).