OS X 10.5.1 Upgrade + Cisco VPN + ‘Error 51: Unable to communicate with the VPN subsystem’ ? Try this.

December 10, 2007 | In: citations

If you’ve recently upgraded to OS X 10.5.1 and noticed your Cisco VPN client reporting a friendly ‘Error 51: Unable to communicate with the VPN subsystem‘ error, you’ll need to do the following.

sudo /System/Library/StartupItems/CiscoVPN/CiscoVPN restart

Essentially the Cisco VPN extension just needs to be restarted.

Thanks to Anders Brownworth for this tip.



5 Responses to OS X 10.5.1 Upgrade + Cisco VPN + ‘Error 51: Unable to communicate with the VPN subsystem’ ? Try this.

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Phil

March 5th, 2008 at 7:56 am

I upgraded to OSX 10.5.2. When I attempted to start the Cisco VPN Client I received Error 51 as above. I tried the fix (sudo command) listed above, but the issue is not resolved. Error 51 appears when I restart the VPN client. I also turned off internet sharing, but Error 51 persists. Any thoughts or ideas would be appreciated.

Thanks

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Phil

March 5th, 2008 at 8:40 am

I upgraded my VPN client from v4.9.0 to v4.9.1 and that resolved the issue.

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Tony

April 7th, 2008 at 1:49 pm

Phil,

How did you get 4.9.1? The Cisco site only has 4.9.01. Is it a beta version?

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Tre

June 19th, 2008 at 7:36 pm

I had the same error and I was using version 4.9.0 but I just installed 4.9.1 and it worked like a charm. Thanks Phil for the info

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Levon

September 23rd, 2008 at 8:28 am

I have the same error showing up occasionally on my group Macs running 10.4.11.

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