Restaurant kiosks are hazardous places, and not only on the side of the screen where patrons jab greasy fingers. On the other side of the glass, things can also go wrong when Windows starts working against the kiosk software.

Spotted in a Portuguese restaurant chain by eagle-eyed Register reader Mário, the screen shows Windows 10 - though it could possibly be Windows 8.x - turning its nose up at a kiosk application. Either way, the sight of it would be enough to put even the most cast-iron sysadmin off their lunch..

In this instance, the WinRestKioskWPF.exe file is apparently lacking a digital signature to verify its publisher. It has therefore failed the Windows 10 sniff test, and a warning is on display.

The problem is that this is a kiosk, so rather than being able to select and enjoy a Portuguese specialty (most likely something with a fried egg on it – if you know, you know), the hungry customer is presented with a baffling dialog. They could press Run (assuming the touchscreen passes input through to the desktop), or they could do the sideways shuffle of shame to a working kiosk.

The software appears to be part of the WinRest suite of Point of Sale software. According [warning: this is an HTTP URL] to the company's website, its tools are "ultra-secure and affordable."

The suffix, WPF, indicates it is a version written with the Windows Form replacement, the Windows Presentation Foundation (WPF).

WPF is an interesting choice for a modern application. It is, after all, very much Windows-only (yes, it was one of the inspirations for Avalonia), but since this kiosk is running Windows, it's not a terrible choice.

Unless, of course, WPF means something different in this instance. We Prefer Frying? It's a possibility. And perhaps also why a clean-living installation of Windows 10 has rejected the application. ®