Hello Riccardo,
Why Include Subfolder is dangerous? Because if you enabled the Include Subfolder feature, AxCrypt will try to encrypt all your files which are all exists in the subfolders of Secured root folders.
If you are having more subfolders and files under the secured folder, then AxCrypt will take extra time to process encryption request. Based on the folder size and system specification, AxCrypt will perform as much as faster.
That’s the reason behind the confirmation message. So no need to worry, just confirm it and secure your files safely.
If you are asking any Queries, please write to Support@axcrypt.net. we are happy to help you.