Microsoft's 1990 Entertainment Pack for Windows, which originally shipped without Tetris, can be found with a sticker added after licensing was secured, making early copies rare.

The pack debuted alongside Windows 3.0 and was released in three subsequent versions before Microsoft ended the series in 1992, though a Best Of edition appeared in 1994 and a Windows CE version followed later in the decade.

Raymond Chen, a veteran Microsoft engineer, explained on his Old New Thing blog that negotiations to license Tetris were still pending when the first boxes were printed, so the company added a sticker once the deal was finalized to avoid waste.

Later print runs incorporated the sticker into the box design, contributing to the collectibility of the original copies.

Chen also noted a separate Windows 95 anti‑piracy hologram that featured a shirtless child, which was replaced with a clothed version after public reaction, illustrating how inadvertent details can become collectible artifacts.

Collectors who still have their original Windows 95 or Entertainment Pack boxes may verify rarity by checking the presence of the sticker or the unclothed hologram.