Last few debian-live images being tested for amd64. We have found a bug with the debian-live Gnome flavour. This specifically affects installs after booting from the live media and then installing to the machine using the Calamares installer found on the desktop. The bug was introduced as a fix for one issue that has produced further buggy behaviour as a result.
Fixes are known - we've had highvoltage come and debug them with us - but will not be put out with this release but will wait for the 10.6 release which will allow for a longer time for debugging overall.
You can still run from the live-media, you can still install with the standard Debian installers found in the menu of the live-media disk - this is _only_ a limited time issue with the Calamares installer. At this point in the release cycle, it's been judged better to release the images as they are - with known and documented issues - than to try and debug them in a hurry and risk damaging or delaying a stable point release.