GeekLab

One of my users got an annoying message when starting MS Paint (mspaint.exe):

Onvoldoende geheugen of bronnen om de bewerking te voltooien. Sluit enkele programma's af en probeer het opnieuw.

Which means:

Insufficient memory to complete operation. Close some programs and try again

Other resources suggested that the file opened was too big or that we're doing something with a .tiff file. But he was just starting paint, no images involved at that point. The solution was to open regedit and remove the following key:
HKCU\Software\Microsoft\Windows\CurrentVersion\Applets\Paint
That reset all MS Paint settings and we could start paint again.