Don’t use any plugins that haven’t been tested with 2.7. For me it was WP-Amazon, which is a known issue on the WP 2.7 compatibility page in the WordPress Codex.

I couldn’t figure out the problem but on one of my blogs that I recently updated, I couldn’t get the upload/insert function to work properly. Instead of opening up the upload/insert dialog over the edit page, wp-admin went to an entirely different page, navigating away from my edit page to the upload/insert form.

After crafty troubleshooting by deactivating all my plugins & reactivating one by one I found that WP-Amazon was the culprit. Hope the developers fix the issue quickly — I like that plugin. So if you’re having trouble with “Coltrane,” check your plugins!