If you’ve been having flashbacks to 2007 while using your PC over the past few days, you’re not alone. Microsoft has mistakenly replaced Windows 11’s boot sound — in test versions of the OS — with the startup chime from Windows Vista.

Windows testers started noticing the issue shortly after Microsoft released its latest Dev Channel build of Windows 11 on Friday afternoon. The .WAV file for the bootup sound, which is stored inside imageres.dll, had been randomly replaced with the Windows Vista startup sound in preview build 26200.5651.

Microsoft quickly acknowledged the mistake, and added a line to its release notes for the latest Dev Channel build. “This week’s flight comes with a delightful blast from the past and will play the Windows Vista boot sound instead of the Windows 11 boot sound,” says the Windows Insider team. “We’re working on a fix.”

It’s not clear how such a mistake even happened, but Brandon LeBlanc from the Windows Insider team joked on X that he “went in and had some fun with the sound files in Windows and thought folks needed a blast from the past,” before confirming that it was actually just a bug.

Perhaps one of Microsoft’s Windows engineers was reminiscing too much about Windows Vista, in a week when Microsoft made it clear it thinks Apple’s new Liquid Glass design bears some resemblance to its Aero Glass look in Windows Vista.