How I fixed the infamous Basilisk II Windows "Black Screen" bug in 2013

Summary

I’ve been noticing a lot of fun stories lately about bugs in old software that suddenly showed up in newer Windows versions. For example, here’s an excellent writeup by Silent about a bug in Grand Theft Auto: San Andreas that laid dormant until Windows 11 24H2 came out. MattKC also recently posted a cool video about the massive project of decompiling LEGO Island, which also solved the mystery of the “exit glitch” that happened in newer versions of Windows. Nathan Baggs has also been at it again, fixing a modern compatibility issue with Sid Meier’s Alpha Centauri this time. I won’t spoil these stories for you, but they all reminded me of a bug that I fixed twelve years ago in Basilisk II but never wrote about until now. Basilisk II is one of the more popular 68k Mac emulators, allowing you to run an old Mac system on your modern machine. Nowadays, you can even run it in your browser using Infinite Mac! Here’s a screenshot of Basilisk II running on my Windows 10 machine. The bug was: when you launched it, the emulated Mac would just sit there with a black screen rather than booting up. It didn’t happen every time, which really confused everybody. The problem seemed to be way more common on newer Windows versions, which were Vista and 7 at the time, but people also occasionally saw it on XP too. It definitely failed most of the time for me with Windows 7. Nobody was seeing this issue on Mac OS X or Linux. To re-familiarize myself with this bug for the purposes of writing this post, I downloaded the broken version from the Internet Archive and tried it out in some virtual machines. Windows 2000 and XP ran it without any trouble on the first try, but Vista and 7 didn’t: Basilisk II has a UI quirk that’s really annoying in this particular situation: the close button doesn’t work. You have to cleanly shut down the emulated machine in order to exit, which is impossible to do when you’re stuck with a black screen. This functionality is useful to protect you from losing data ...