Deleted files due to mirroring. How to recover?

[Randomuser237648]

Need some help. I mistakenly set the synced to mirroring instead of updating the drive and it deleted over 8tb worth of pictures and videos. FAQ said there is an undelete tool but where is this tool or function? I also went to a data restoration company and I'm not positive they are able to find them. Any help would be great appreciated.

[Plerry]

The obvious answer to your question is: from your backup.
But it seems that, like many before you, you now learned the need to have backups the hard way )-:

As far as possibly still being able to recover your data:
It depends on how you have set your "Delete and overwrite" option in your FreeFileSync Synchronization Settings (F8).
By default, this option is set to Recycle Bin, so that may then be the place to look.
However, you lost 8tb of data, which may have been too much for your Recycle Bin to hold, depending on your OS settings.

[xCSxXenon]

The FAQ mentions using a tool but doesn't mention any specific one. These tools are very unlikely to work. They don't work with SSDs, as those trim themselves very frequently. With HDDs, it's more likely but still very slim ,and the choices are riddled with endless scams and fake software. A data recovery specialist is the best chance, but also the most expensive. As a data recoverer, I would be wary of any local place as destroying the remaining slim chance of recovery is very easy.
Ultimately, as Plerry said, restoring from a backup is the only real answer to this question.