Update photo embossing

Hi,
I'm using the Emboss Module for years with my Gallery v3... (now 3.0.9), but this is not important.
I have more than 20000 images in my Gallery using emboss.
But I have a problem running "Update photo embossing" (see attached screenshot).
The batch job stops always on file 16691 and if I try to restart it it only shows me "Starting up..." and nothing happened if I wait for the process.

I have tried to disable all Overlays (and press "Update") and resign the chosen Overlay start again... then it starts and after the image 16691 it stops again.

Maybe someone has an idea to help me or find the problem.

Thanks in advance.
Stack