CUCM 7 error switching versions

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Jul 29th, 2009
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I added this to an existing thread over on the applications bb, but I know more people watch this bb and hope someone might have any tips.

Basically I upgraded a single server from 6.0(1)a to 7.0(2a)SU1 -

When I try and switch back I get an error "Sync after switch version failed".

When I try from cli the "utils system switch-version" command doesn't have the option of "nodatasync". I've used that command successfully before on other versions of 6.x and 7.x, but for some reason it seems to be missing from 7.0(2a)SU1.

Has anyone seen this problem and managed to find a way of switching back? Many thanks.

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billybjo1 Wed, 07/29/2009 - 03:47
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Actually I've fixed the sync problem, it was a DNS issue. TAC are going to progress the missing [nodatasync] issue.

Brian Carlson Thu, 08/13/2009 - 16:12
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Hi I had this same issue today where I received a "sync after switch failed" error. The problem turned out to be with DNS, make sure you are able to resolve the hostname of the server, not just it's fully-qualified-domain-name (FQDN).

For example if your server is named SERVER1, make sure SERVER1 resolves, and not just

With my server, was resolving, but not SERVER1. Once I added an entry in DNS for SERVER1, I was able to switch versions without issue.


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