I can't think of anything else I am afraid, so I'm going to try a couple of slightly silly/hopeful suggestions ....
Is the error message about needing to upgrade really an error message, or just a warning that an upgrade is available?
Sometimes you can carry on by ignoring such messages; either dismissing them or just pushing them to one side.
What machine/OS are you on?
Is it definitely v1.7.2 you are using as the earlier version, not just some other earlier version?
I seem to remember someone else with similar issues that turned out to be because they were using an even earlier version.
That person was on a Mac; I don't know if that was a releavant part of it.