I'm currently using Build 9310 on a late 2009 17" Aluminum MacBook Pro, 3.06 GHz, 8 GB RAM, running OS X 10.6.2 along with Apple 30" Cinema Display. I encountered the "Cannot switch to Coherence" error whenever invoking either Coherence or Crystal mode. Strangely, this only occurs when I invoke the option when the PD VM window begins from the 30" Cinema Display. Thus, if I were to invoke either of the Coherence or Crystal mode when the PD VM window is starting from my 17" screen on my laptop, even while the 30" is active, the mode converts without a hitch. Moreover, I can then drag any of the Windows screen to the 30" Cinema Display area and the emulation works without a hitch. Even though I've addressed the issue with a workaround, this is obviously this is a bug that needs to be addressed.