Sorry for the late reply Gunther, been a bit busy. :-(

I'll do and will observe the problem furthermore. Is this something that could be fixed or is this out of your hand since you don't have control overEXIFtool?

Normally this shouldn't occur anymore. In older versions of LRT ( <1.7)the connection between LRT and ExifTool could break, but since I fixed that I didn't observe those issues anymore. I'm convinced that you still have old (wrong) preview stubs, so it might make sense to delete the whole stubs folder and let them get refreshed.