I did that - and copied my configs from the problematic app to it. It was working - like magic. Files with blank allowed, all files displayed (I tried some from the end like zip, xls, ...).

 

I then copied the default.config back to my own application (same date and time) and overwrote it. I recycled the pool - and now it is working there, too.

 

Thanks for your support.

 

I am not sure how to set something to solved here - so please feel free to do it.

 

I do not know how to get email on replies - so I checked some days later.