I really don't know. It didn't happen to me when I swapped over to pro or changed various versions of LW in either Mac or Windows. I think this is the 1st time I've heard of it happening on the forum. Sometimes there's small issues changing over to pro but no not this one.

All I know is corrupt downlds generally come from the source, or alternatively there's some type of interference b/w the uplder & downlder, or there's an aggressive firewall involved somewhere. Oh & I have heard of anti-virus, etc. utilities having an effect when not properly configured.