The Old New Thing

Practical development throughout the evolution of Windows.

Latest posts

Jul 3, 2026
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How did we conclude that CcNamespace.dll was the ringleader of a group of DLLs that unloaded prematurely?

Raymond Chen

Contextual clues.

Jul 2, 2026
Post comments count 6
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The case of the thread executing from an unloaded third-party DLL

Raymond Chen

Oops, I didn't realize that I was still doing that.

Jul 1, 2026
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It rather involved being on the other side of this airtight hatchway: Changing administrative settings

Raymond Chen

Unlocking the door from the inside.

Jun 30, 2026
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2026 mid-year link clearance

Raymond Chen

Made it to another midpoint.

Jun 30, 2026
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A compatibility note on the abuse of Windows window class extra bytes

Raymond Chen

Finding an illicit place to hide data.

Jun 29, 2026
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The evolution of window and class extra bytes in Windows

Raymond Chen

The intended usage is encoded in the prefix.

Jun 26, 2026
Post comments count 21
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The case of the DLL that was not present in memory despite not being formally unloaded, part 2

Raymond Chen

Tying two bugs together.

Jun 25, 2026
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Raymond’s hot take on Hainanese chicken

Raymond Chen

Subtlety.

Jun 25, 2026
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The case of the DLL that was not present in memory despite not being formally unloaded, part 1

Raymond Chen

Figuring out how it went missing.

Jun 24, 2026
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Cancellation of Windows Runtime activities is asynchronous

Raymond Chen

You're asking for it to cancel, but it doesn't wait for confirmation.

Jun 23, 2026
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Microspeak elaborated: Isn’t escrow just a release candidate by another name?

Raymond Chen

Yes, but the name is a psychological trick.

Jun 22, 2026
Post comments count 26
Post likes count 17

In memory of the man who put red and green squiggles under words

Raymond Chen

Starting in Word and expanding to nearly every other word processor, and even things that aren't word processors.

Jun 19, 2026
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What does it mean when the bottom bit of my HMODULE is set?

Raymond Chen

A special kind of <CODE>HMODULE</CODE>.

Jun 18, 2026
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Why doesn’t Get­Last­Input­Info() return info for the user I’m impersonating?

Raymond Chen

It doesn't care about impersonation, says so on the tin.

Jun 17, 2026
Post comments count 6
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Windows stack limit checking retrospective, follow-up

Raymond Chen

Choosing the register to use to pass the desired stack allocation size.

Jun 16, 2026
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Retrofitting the WM_COPY­DATA message onto Windows 3.1

Raymond Chen

It was carefully designed to be trivial.

Jun 15, 2026
Post comments count 28
Post likes count 13

The time the x86 emulator team found code so bad that they fixed it during emulation

Raymond Chen

Offensive content in the eyes of a software engineer.

Jun 12, 2026
Post comments count 8
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How can I schedule work on a thread pool with low latency?

Raymond Chen

The thread pool is designed for throughput, not latency.