We've just made Sandvox 2.6.5 available using Check for Updates, if your version of Sandvox supports that. There is essentially just one change in 2.6.5 from 2.6.4 and that is a fix for Mountain Lion users publishing using FTP.
Update, 23 August 2012: Apple just approved 2.6.5 today and it is now available on the Mac App Store. If you are a Mac App Store customer, just launch the App Store app and check the Updates tab.
Update, 9 August 2012: Since we just got approval for 2.6.4 on the Mac App Store, we can now submit 2.6.5 for approval. It is hard to predict how long approval will take, but hopefully no more than a week or two for 2.6.5.
If you're not yet on Mountain Lion and/or not using FTP to publish your site, the 2.6.5 update is not critical. It really just fixes that one issue.
Here are the complete notes for 2.6.5:
fix for issues under Mountain Lion when publishing via FTP