Before Microsoft owned the world, back about 1974 (I think), they sold the best BASIC language software there was. It was a code image for the CP/M OS. But it needed more memory than most microcomputers had at the time, so they came up with an idea to make their own Dynamic Memory board and bundle it with the BASIC software.
Unfortunatly, the boards did not work. But they sold them anyway. In fact, Microsoft said that they would not sell Basic except with the Memory board. So people that needed the BASIC had to buy a board that everyone knew did not work, then buy expensive static memory boards from someone else.
We were in college at the time, and decided to find out what was wrong with the boards. The best we could determine (since dynamic memory was still experimental at that time) was that the skew in the strobe pulses had them out of timing when they got to the chips. So, we tried to redesign the board, cutting and jumpering runs and adding different control chips. But the memory chips themselves did not work in a way that could be made to operate on the S-100 bus protocol.
Either none were ever tested by Microsoft, or they failed and were sold anyway.
So far as I know, none of the Microsoft Dynamic Memory boards ever worked, for anyone. It would have been news in the industry!
But Microsoft continued to refuse to sell BASIC unless you bought one of the boards, until they were gone. Somewhere there are buried hundreds of Microsoft 4K Dynamic Memory boards, that never worked.
There were stories about it in copies of BYTE Magazine of the time, I think. (Or maybe it was an earlier magazine.)