I wonder if this is a new problem? I have never had any issues writing a file. But I have also only used it with the Infinity and 460ex. But I do have the Horizon on order.
I had the problem arise again last night. My first imaging session worked like a charm; wrote the OnScreen image to a TIF file, no problem. My next four imaging sessions wouldn't allow a TIF or PNG file output; had to save the OnScreen images as FIT, the only write format that would work!? Almost as if the software forgot how to convert the output to TIF or PNG!?
I've never had the problem with my Infinity or 428Ex cameras and have only seen the problem with the most recent release of the software.
bwa