Has Microsoft ever offered an explanation for why they require CTRL+ALT+DEL to login? (Yes I know you can disable it, but it is still their preferred method.) It seems like at one point I heard that it was for security since you knew nothing else could trap CTRL+ALT+DEL, but I've written programs that trap CTRL+ALT+DEL, and it isn't that difficult, so I am pretty sure that was just a myth, either that or the decision to require CTRL+ALT+DEL is based on a fallacy.

Either way, I am curious if there is an official reason, and if that reason has any actual merit.


  • This is a well known key sequence by every Windows users
    – Kami
    Nov 19, 2009 at 9:39
  • 2
    Before that, it was a well known key sequence for every MS-DOS user Dec 17, 2009 at 0:28
  • 2
    How can you trap the ctrl+alt+del key? Even remote desktop or virtual machine softwares cannot do that and must implement an alternative for this
    – phuclv
    Oct 22, 2013 at 9:19
  • This question was re-asked as What makes Secure Login (CTRL+ALT+DEL) Secure?, where it got pretty much the same answer. Apr 30, 2015 at 21:27

1 Answer 1


This is the same as this Server Fault question: How does CTRL-ALT-DEL to log in make Windows more secure?.

Here is the accepted answer from there, by Oskar Duveborn:

The Windows (NT) kernel is designed to reserve the notification of this key combination to a single process: Winlogon. So, as long as the Windows installation itself is working as it should - no third party application can respond to this key combination (if it could, it could present a fake logon window and keylog your password ;)


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