Why do I lose my USB speakers after reconnecting with VMWare Fusion 3 running?
When a USB device is hot-plugged while VMware is running, I often see a dialog from the VM instance asking if the device should be attached to the VM or to the host OS. It's quite easy to miss this dialog if you have other applications running or if the VM is in a separate workspace. And until the dialog gets its answer, the device isn't attached to either OS.

If you're not seeing this dialog, it's also possible that VMware has already been configured with a default answer for the device in question. For example, it might automatically be attaching the device to the guest OS running in your VM. Note that this is not normally what you'd want with USB speakers, as VMware already emulates a virtual audio output device for use by guest OS's that funnels audio output through the host OS.

Have a look at your VM settings under "Virtual Machine > USB &amp; Bluetooth Settings…" where you should see a dialog similar to the following:



I expect you should see an entry corresponding to your USB speakers. If so, you should be able to configure how they're handled when hot-plugged from there.