# Marcin Kleczynski on Reddit (u/mkleczynski)

Part of Founders and CEOs on Reddit, researched with Autumn (https://www.autumn.ai) from public sources. Updated 2026-11-07. Interactive version: https://www.autumn.ai/resources/founders-on-reddit/marcin-kleczynski

Marcin Kleczynski: Founder and CEO of Malwarebytes.

- Reddit account: [u/mkleczynski](https://www.reddit.com/user/mkleczynski/) (Personal account)
- How we know it's theirs: [His 2012 r/IAmA AMA, posted from this account](https://www.reddit.com/r/IAmA/comments/119cyf/)
- Where they post, in the records we retrieved: r/IAmA (10), r/technology (2), r/sysadmin (2), r/todayilearned (1), r/AskReddit (1), r/cybersecurity (1)
- Known activity in the posts we found: 2012 to 2021
- Wikipedia: 

## Moments

### u/mkleczynski in r/IAmA, Oct 10, 2012 · Fixed it

Replying to a redditor:

> Am I the only person who's annoyed by the way, when you manually update Malwarebytes definitions, and then accidentally highlight another window while it's downloading (, that you can't just tab back to the update window when it finishes because it hasn't created anything in the…

> Nope, I just tried it and I'm annoyed. Off the to development queue it goes.

Full thread: https://www.reddit.com/r/IAmA/comments/119cyf/iam_marcin_kleczynski_founder_and_ceo_of/c6kguir/ · 927 points as of Nov 7, 2026

### u/mkleczynski in r/IAmA, Oct 10, 2012 · Early days

Replying to a redditor:

> Just wanted to say thank you. Spent three years working in a local computer shop and about every computer was fixed thanks to malwarebytes.

> You're welcome! I worked at a computer shop where we reformatted every. Single. Machine. I couldn't take it anymore.

Full thread: https://www.reddit.com/r/IAmA/comments/119cyf/iam_marcin_kleczynski_founder_and_ceo_of/c6kg4qy/ · 373 points as of Nov 7, 2026

### u/mkleczynski in r/technology, Sep 23, 2015 · Fixed it

Replying to the post "Malwarebytes is now blocking compromised IP ranges from imgur.".

> Marcin from Malwarebytes here! I'm looking into it personally.

Full thread: https://www.reddit.com/r/technology/comments/3m1tq7/malwarebytes_is_now_blocking_compromised_ip/cvbggh4/ · 621 points as of Nov 7, 2026