I am using AutoItX, but was using AutoIt documentation (since that is what comes up in Google Searches). I found a discrepency in the functionality of WinWaitActive. Initially, I thought I was just using an old version of the DLL, but I ruled that out and now see that my observed behaviour is in agreement with the AutoItX documentation. However, this would make it at odds with the AutoIt behaviour, so I want to confirm with the experts out there: WinWaitActive AutoIt: Return Value Succ