UPDATE Mar 14 2013: This issue is resolved with the 10.8.3 software update for Mountain Lion.
Over the last 24 hours, we've become aware of a specific issue affecting Harmony customers.
What is the issue?
If you purchased Harmony from the Mac App Store, Harmony 2.5.3 and later is unable to communicate with Accordance on OS X Mountain Lion. Therefore, Harmony's scripture feature does not function.
Do the Mountain Lion 10.8.1 or 10.8.2 software updates resolve the issue?
The 10.8.1 and 10.8.2 updates do not resolve the issue.
What is the current upgrade advice?
We are advising Harmony Mac App Store customers to avoid upgrading to OS X Mountain Lion, if they use Harmony with Accordance, until the issue is resolved.
What can I do if I've already upgraded to Mountain Lion and I'm encountering the issue?
Forward your Mac App Store receipt for Harmony to support at sweeterrhythm dot com. We will issue you instructions and a coupon code to use the "direct edition" of Harmony at no charge.
What is Sweeter Rhythm LLC doing to resolve the issue long term?
We have opened a call with Apple's developer technical support and are continuing our own troubleshooting.
UPDATE Aug 28, 2012: We have confirmed that this is a caused by a bug in OS X Mountain Lion, without a workaround at this time. The bug may be fixed in a future Mountain Lion software update.
What differences exist between the Mac App Store edition of Harmony and the direct edition?
See this help article for more information.