Plugin stopping in every kind of conversions

Hi,
I installed ImageMagick months ago and now I wanted to use it – why does the regenerate progress end in random places – sometimes to 4 %, sometimes to 29% and so on? I have tried to select only 1 type of images to generate at times, but it does not progress after a while. Then I restart and it goes again and stops.

Any tips what should I be checking? I have used the plugin in default mode “ImageMagick command-line”