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VMWare Fusion – Network Bridge error finally solved

A couple of years back, I posted this thread about an annoying problem in VMWare Fusion which occasionally stopped me from being able to run an image as in bridge mode.

Well, looks like I’ve finally sorted this one out.  I don’t know if it’s the inclusion of new functionality in v2 or v3 of VMF but after doing the below, I’ve not seen the problem occur for a couple of months now.  I can still easily reproduce this issue so I’m guessing it’s some kind of defect in the adaptor autodetect code [or a problem with my config somewhere].

To reproduce the problem, firstly the environment:

  1. My MBP is connected to a wireless network only, running WPA2.
  2. I’m running VMWare Fusion 3.0.2 (232708) on OS X 10.6.2 (Although this occurred on VMF v1 and v2 as well as OS X 10.5).
  3. The VM is Windows 7 Ultimate (although this occurred with Win XP also).

Here is a screenshot of the VM network settings that cause the error message “The network bridge on device /dev/vmnet0 is not running”:

VMWare Fusion Network settings - autodetect

Choosing auto-detect breaks bridge networking every single time.
Fortunately the workaround is very simple.  Setting it to use a specific network adaptor fixes the problem immediately.

VMWare Fusion Network Settings - Specific adaptor

The down side to setting the specific adaptor is that when I’m in an environment without wireless and I need to use ethernet, I have to remember to change it in here.  I know that’s not a serious problem but it is irritating when I realise my MSN client has been disconnected for hours.

There have been a bunch of people commenting on the older post and it’s actually now my ‘most hit’ entry (finally overtaking the Outlook 12 beta one) so hopefully this will be of use to some people.


[Update: March 12th 2010 17:00ish]  Well, I got an @ from @VMWareFusion this afternoon saying “@ianmcshane BTW, we tried to repro this internally with your steps and it works just fine for us. There is something else missing here.”

So I guess YMMV but selecting the specific adaptor has certainly allowed my VM images to run in bridge mode.


  1. […] UPDATED MARCH 12 2010:  I just posted my solution to this problem here […]

  2. I’m having a similar issue since re-installing my MBP. Did you have any luck with the resolution?

    NAT works fine. Bridged (selected or auto-detect) don’t always pass traffic.


  3. Ian says:

    I moved to Parallels….

  4. Steve says:

    Using VMWare Fusion 4 and had a similar problem – your solution worked for me.

  5. Anthony says:

    Thanks Ian – you just saved me a lot of grief!

    This issue just started appearing on my iMac with Fusion 4 and Ubuntu 11.10 as the guest. The weird thing is that I run another guest (concurrently) with Windows XP and it doesn’t seem to happen on it (yet).

    Another oddity is that I don’t use my Wifi adapter on my iMac and only use my wired connection so you would think that the Auto selection would default to the only connected adapter on my iMac.

    VMWare really should take a closer look at this issue.

  6. Anthony says:

    I think I figured out the issue – at least mine. I was connected to my work VPN at the time! When I disconnected from my work VPN the Auto Detect option functioned properly again.

  7. Len says:

    Your solution also works for Fusion 6, where this is apparently still a problem.

  8. Antti says:

    For me this was solved by turning off Mac firewall

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