Cannot enter coherence mode in Parallels Desktop 9

A recent update has produced a lot of comments about not being able to switch in to Coherence Mode in Parallels Desktop 9 - here’s a work around that works for me.

I’ve come back from leave to a number of people commenting how
coherence mode no longer works. I tried a few things for a few people - without much effort to be fair - and found that they were right, and it didn’t work...but it worked well on my machine so..... and then a Parallels Update came through, and boom, mine no longer worked either. This, I have to say, focussed my mind somewhat more on the issue as I particularly like coherence mode.

Anyway, after some playing, it seems the issue is nothing more than the amount of RAM allocated to the graphics card in your virtual machine. My default work VM, and a lot of other people’s who were experiencing the issue, had the Video Memory set at 256Mb or less - mine was on 256Mb.

Upping this figure enabled Coherence mode to work again. The odd thing is that upon looking the smaller memory aperture for the Video Card works on *some* MacBooks, but not others. My guess is that it’s related to the age of the units, and the type of graphic cards installed in them? For example, on my late 2013 Retina MBP and my late 2011 17” MBP it *doesn’t* allow coherence with a 256Mb Graphics Card aperture, but on my 2011 Air it does? Anyway, life is too short for me to work out the detail, but if you’re having the issue it’s easy enough to fix.

Go into the configuration option, and then into ‘hardware’. Pop to the ‘Video’ option and up the Video Memory from 256 to ... something more - for me, that’s allowed coherence to work properly on both my 2013 & 2011 units.


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