Performance issues with VMware Fusion and OSX Mavericks App Nap

I recently upgraded to OSX 10.9.1 and while most of the upgrades to OSX are welcomed I have been noticing some strange and inconsistent performance issues with VMware Fusion 6.

I knew the issues probably had something to do with Maverick’s as I had no issues with my Mac when using Mountain Lion. I dug a little deeper and looked at the newly  refreshed Activity Monitor in OS X. Nothing exceptional in the CPU and Memory tabs. CPU was at a reasonable level before and after running a virtual machine in VMWare Fusion and I have plenty of room with 16GB of memory.

Nothing seemed to be pegging either metric.  I

looked at Disk and Network… again nothing out of the ordinary.

Knowing that Energy was a new tab I haven’t seen before in Activity Monitor I selected it and noticed the “App Nap” column was listed and indicated “Yes” in the row defining VMWare Fusion.

App Nap is the new feature in Mavericks that allows users, thankfully, to allow OSX to put to sleep applications consuming excessive amounts of your limited battery power.  A great feature for laptop users but I’m using a desktop and plugged into AC.  Not as big of an issue at my desk.  

 

 

A quick scan of Apple’s support site led me to how to disable this feature on an app-by-app basis…  Here’s what I did:

1.  Open a Finder window and navigate to your Applications Folder

2.  Locate VMware Fusion, right click and select “Get Info”

3.  In the “General:” section of the dialog box you will see a checkbox for “Prevent App Nap”.  Make sure this is unchecked.



I terminated and restarted VMWare Fusion and launched my Windows virtual machines and everything returned back to normal. No more performance loss or stuttering.

Hope this helps!