I'm setting up my last machine for my wife for gaming. Athlon X4 630, and 16 GB of RAM. I loaded windows up and said it had ~2 GB free and I was like "oh crap, the RAM sticks must be dead" (because the last motherboard that I just replaced broke some RAM slots).
I fixed my old video card, a GTX 560, and wanted to see what it could run. I loaded steam and PUBG said "invalid platform error". It took me a moment. I hit alt-pausebreak, presto, Windows 32-bit. Whoops.
Hadn't had that problem in a long time except at clients running ancient windows server versions complaining about why Exchange 2003 won't work with their iPhones anymore "it used to work and we didn't change anything!" (Yeah... but the iPhone DID change--including banning your insecure 2003 Exchange protocols.)
Took me a good day's worth of debugging before some bright spark piped up and said "wait, you said you were on x86-32...?"
...yeah, I use really old computers.