Talks to Watch

Why You Can't Name A File CON In Windows

7.8M views · Apr 20, 2020 · 8:03 · 0 HN recommenders · 4 mentions · discussed 2020–2026

Tom Scott explains why Windows does not let you name a file CON, tracing the reserved device names back to backwards compatibility with DOS.

Why Hacker News points people here: Linked as a relevant explainer in threads about Windows quirks and reserved names.

“relevant video”HN comment, 2020

What Hacker News said 4

Cites itgresrunApr 2020
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Excel also has a deliberate bug where it thinks 1900 is a leap year because they wanted compatibility with Lotus 123, where the bug was actually a bug! [0] [0] this video

Cites itirshadshaluJun 2020

“relevant video”

Why reserved device names persist in Windows.

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can't speak about the very recent updates, but windows have been consistent and adamant on keeping the backward compatibility. they still use reserved file names for io devices so that 30+ year old printers can still work, and you can still open a 2000s doc file in office 365. (I'm looking at you Apple, who made many of the 32 bit apps I loved useless) relevant video: this video (Tom Scott: Why you can't use CON as filename in windows)

Cites itRajT88May 2023

“Somehow over all those decades, I've never tried to do this until Tom Scott made a video about it”

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It's wild to me some of the things I never knew, even though I've been using Windows or DOS for probably 35 years. For example, I recently learned you can't name a file CON. Try it. Somehow over all those decades, I've never tried to do this until Tom Scott made a video about it: this video

in “The .zip TLD sucks and it needs to be immediately revoked” · view on HN
Jokecardboard9926Jun 2026
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Don't think this will ever happen, especially since this is Microsoft you are talking about [0] [0] this video