Sentinel-1 appear Black after a chain processing

Hello everyone, I am using SNAP Version 7, and I would really appreciate your kind help. I have a bunch of Sentinel -1 images after a processing chain (orbit file, thermal noise) then (calibrated to sigma naught, filtering, Range Doppler terrain correction). However, when I try to open the images, most of them appear to be black. In addition, the image took a
long time before they open in the SNAP. Could you please give a piece of advice or any Suggestion on what goes wrong?

Thank you!

Can you tell after which step they became black?
It is usually good to check each intermediate product for errors when applying larger processing chains.

Thank you very much for your response.well, I cannot states at which step, Because first i applied orbit and Thermal Noise at once, then the remaining processing. But now, I start a new processing one-by-one from Orbit file and Thermal the image is Ok.

Doing it step by step once would be good to see where the error occurs. Once the step is idenfitied, we can think of how to eliminate it and then you can go back to batch processing.

Ok, Thanks I’m doing now.