PinballY system program not found
What it means
A PinballY system is set to start its games with a program that is not at the given place on this PC.
Why it happens
The system's « Program EXE » setting holds a full path, and the file is no longer there: it may have been moved, renamed or uninstalled after the setting was written. The scan cannot tell which of these cases is yours.
How Pincab Toolbox detects it
The scan reads PinballY's Settings.txt. For each enabled system whose « Program EXE » is a full path, it checks that the file exists. It says nothing for a disabled system, for a program left to Windows' file association, written as a relative path or started through Steam, nor if the drive of that path is not on this PC. Nothing is changed.
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. Partly covered, read only: PinballX and PinballY (their settings and game lists). Not covered: Future Pinball, Pinball FX, Visual Pinball 9 and the other frontends.