I use Amazon S3 for my Woocommerce store. Some of the files that I offer are Adobe PSD files.
For some reason, when I test download one of my PSD's from my online store, it downloads fine, but won't open, the file is corrupt.
When I download it direct from Amazon S3, it downloads and opens fine, so I'm thinking it's your plugin.
Do you know of any compatibility issues with PSD files?