April 13, 2026, 3:04 pm | Read time: 4 minutes
With the Windows operating system, Microsoft likely achieved its greatest success. However, not everything the company developed was well-received by users. One product has gone down in company history as the biggest misstep to date.
Microsoft is one of those brands that almost everyone has heard of. The Windows operating system really accelerated the development of computers. Suddenly, everyone wanted to own one of those gray boxes, even if many had no idea what to do with them. That’s why it sounds incredible what a Microsoft developer confessed in a blog post. A specially developed software for the Mach 20 reportedly sold only three times. We’ve taken a closer look at this #BigFail.
Overview
Microsoft’s annual revenue has been in the triple-digit billion range for some time. A Microsoft software that reportedly sold only three times sounds like an encounter with the Yeti—highly unbelievable. According to Microsoft employee Raymond Chen, that’s exactly what happened when the company developed special software for an expansion card in the mid-1980s.
Mach 20 Expansion Card Speeds Up the PC
An expansion card can best be compared to a memory card for smartphones. But we’re talking about a large component from the early days of the computer industry that could be plugged into the motherboard, the brain of the computer. Such an expansion card was used to increase memory and speed up the computer. At the same time, the card had additional slots, for example, for a mouse. Such slots were scarce then, as they are now.
Microsoft saw a good business opportunity in expansion cards. However, the company could have been warned. An initial prototype named Mach 10 had already flopped significantly. But that didn’t stop the company founded by Bill Gates from producing the successor Mach 20 with the Portable Computer Support Group; even faster, with more memory and more slots. All this at the bargain price of just under $500. For comparison: A new computer cost around $4,000 at the time.
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The Issue with Tax Law
The price, according to Microsoft developer Raymond Chen, was the decisive factor for launching the Mach 20 on the market. Here’s a brief excursion into accounting and tax law.
Computers were considered office machines in the U.S. at the time. These could be depreciated over seven years for tax purposes. However, the technical development of PCs advanced faster than accountants could record. Therefore, the seven-year rule suddenly became a problem. The old computer might be outdated after two or three years, but it still appears in the books and hasn’t been fully depreciated.
This is where Microsoft stepped in with its Mach-20 expansion card. Instead of replacing the old PC with an expensive new computer, simply revitalize the old machine with the Mach 20. That was the marketing theory.
Mach 20 Becomes a Colossal Flop
The customers didn’t buy into it. The sale of the hardware, the Mach 20 itself, was sluggish. Apparently, customers didn’t quite understand the marketing department’s reasoning at Microsoft. Microsoft then tried to lay another bait with software specifically developed for the Mach 20. But even OS/2, the operating system for the expansion card, didn’t make the cash register ring faster.
On the contrary: In the memory of Microsoft developer Raymond Chen, eleven people bought the software. However, since it didn’t work smoothly, eight buyers returned OS/2 for the Mach 20. Whether the three remaining owners were happy with the software is not known. It also remains a mystery what consequences this mega-flop had for Microsoft.
Ultimately, the expansion card and its accompanying software hit the market at a time when the technical development of new computer systems was gaining momentum. The increasing supply led to falling prices. Simple formula: The Mach 20 quickly appeared very unnecessary in this environment. Overall, this story didn’t harm Microsoft and remains a minor footnote. Nevertheless, the OS/2 operating system for the Mach 20, with only three sales, is definitely one of Microsoft’s biggest flops.