Hello Jim,
In general, the “Shred and Delete” option should not be treated as a full data sanitizing operation. It’s very, very hard with modern hard disks (even mechanical) and SSD is particular to ensure that you’re really overwriting.
That’s why for example real-world intelligence service “Shred and Delete” is done like this: https://www.theguardian.com/uk-news/2014/jan/31/footage-released-guardian-editors-snowden-hard-drives-gchq instead of using sanitizing software of any kind.
The AxCrypt Shred and Delete options asks the file system via the operating system to overwrite the data as explicitly as possible, that’s it. There are no provisions for layers between saving copies, or in the case of SSD’s actually writing somewhere else due to wear levelling algorithms etc.
In actual use it works well enough to stop normal recovery operations and software to work in most situations, but armed with low-level forensics firmware and such, some or all information depending on the situation can probably be recovered.
Our suggestion is to use hard disk encryption (BitLocker and/or EFS) together with AxCrypt to beef up the security of the local PC, and to protect in case of the actual hard drive going AWOL.