Why there no Windows 9

A few people have asked and I saw a post on Reddit yesterday from someone claiming to be a dev at MSFT.

It’s because of compatibility issues.  A ton of code was written back in Windows 95/98 days that does a .StartsWith(“Windows9”) check to see if the app can run.

So that pragmatic answers makes sense to me.


This is technically Windows 6.4 for similar reasons.  Developers back in the day used to write code looking for things that were greater than 6.1 before running (back in Vista’s days).  If Windows reported itself as 7 a whole lot of code would fail.

internal bool SupportsTaskProgress() {
    if (System.Environment.OSVersion.Version.Major >= 6) {
        if (System.Environment.OSVersion.Version.Minor >= 1) {
            return true;
    return false;



// Dave

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2 Responses to Why there no Windows 9

  1. And I thought it was because 7 8 9.

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