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Secure Delete a partition with SDelete

I somehow managed to get all the data from my broken HDD. Before describing what I did there the more interesting part:

How to securely delete all your data on your HDD in Windows, while you do no longer have files but free space.

If you don’t even have partitions anymore  create one.
If you still have a partition, make sure it’s totally empty. Do a quick format to delete all files and to also delete journaling and recover files.

The MS Sysinternals Suite includes SDelete, a small command line application which can securely delete files or free space.
To clean all free space on a partition, call it with something like

sdelete -z D:\

-z for cleaning free space.

So much for theory. Was not sufficient. I was still able to recover files with Recuva.

Now I just deleted all partitions on the HDD, created a new one spanning over the entire HDD and did a format (non-quick ofc) and it seems to be ok. Recuva can’t find files anymore. Not even with deep-scanning.