Bleachbit shredder on flash drives ?


I heard different theories about using the shred function on a flash drive (USB drive, or Micro-SD).
So, is it useful for permanently deleting data, or must I use another software (and if that's the case, do you know which one, preferably on linux ?)

What kind of theories?

There are different levels of deleting with different trade-offs between convenience and security:

  1. Standard delete from operating system: recovery is fairly easy with easily available tools
  2. Overwrite free space
  3. Wipe entire partition and reformat
  4. Physically destroy the storage device

BleachBIt does #2. It is permanent and rather thorough, but it does not cover allocated space, slack space, and bad sectors. For many uses, this is fine, and it is fast and convenient. Of course, what is "enough" depends on your particular use case.

See also the documentation Shred files and wipe disks

Andrew, lead developer

Thank you for your reply. I think my question was unclear.
I was referring to the "wear leveling" system. Many people now say that shredding flash-based drives isn't useful at all, and data can be recovered very easily even after many swipes (I know your position about that, and I read your documentation, by the way), at the point shredding flash devices is almost inefficient.

Some links, maybe :

"But - there is a big issue with flash drives when erasing by overwriting. The problem is the "wear leveling" methods used on solid state drives, which writes in a different place each time you add or replace data"

Another link :
"Unfortunately due to the way SSDs, USB flash drives, and SD cards work, it is difficult, if not impossible, to securely delete both individual files and free space."

I'd be happy to have your opinion. Is Bleachbit shredding uneffective with SSD/USB/SD drives ?

Does someone have an opinion ?
It's a shame I don't have an answer since the bleachbit forum seems more reliable than others websites.


Hello. Sorry for the late reply.

Overwriting free space on a HDD is very different then how it works on a SSD. Currently, BleachBit is mostly for HDDs.

The shred feature works differently then overwriting and since this is done on disk access, you can shred the files just fine on a SSD, however, there is still the issue of write data. Shredding a file is obviously not like putting it into a shredder like you would in real life. It has to use passes. This overwrites content on it. BleachBit only uses a 1 pass wipe because other methods are a waste of time, however, even a 1-pass can be a issue on a SSD. With a 1 pass on a 1gb file, that would mean that it will have to write 1gb of writes to the drive. This can easily wear off the SSD life-span, since SSDs depend a lot on how much data is written to it.

This is much more you can read about or I can explain more if you want, but I hope this answers your original question.

Also known as Alex.

Moderator for BleachBit and a maintainer for Winapp2.

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Windows 10 x64 (switching to ReactOS in the future).