Waveform Free

I am using waveform 11 free and having problems when trying to render a file. Some edits render no problem at all but 1 particular edit just does nothing. All edits have the same settings/options as far as I can see.

being a newby I have hit a brick wall and being free version Tracktion is offering no support.

all suggestions gratefully received.

thanks.

na vdd a versão teste tem um limite de 30 dias....nada de free...somente teste de 30 dias.