I recently installed Windows 7 in VirtualBox, and unlike other OSes I’ve installed in VirtualBox, the sound driver wasn’t automatically recognized. I found a driver that works with both 32-bit and 64-bit versions.

VirtualBox Windows 7 Driver

I installed this both before and after installing the Guest Additions, but it didn’t matter what order the driver and Guest Additions were installed in.

Enjoy. 🙂

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