In the session section add an option to tag host for recreate.

An option to tag a host to either become unavailable when user signs out or to recreate itself on the next sign out would be a good feature for times when you don't want to disrupt the logged in user, but when they sign out you want their machine to not go back into the pool. SO you can tag it to either recreate or not be selectable in the pool until you deal with it and release it back. *Hope that makes sense*

We have hundreds of users spread across 4 image pools... so when I need to add a feature, I don't use the maintenance mode because it literally logs out all users and recreates the machines and that is not a good method (and some issues can't wait until off the clock)... If the maintenance mode actually just updated the gold and then only recreated the non-logged in users, and removed the old images as they became available, it would be more operable but since it doesn't... I start up the Gold image outside the client and make changes, and then shutdown the gold image again. Then if a specific user needs to new image right away, I have them log out and I assign them a new image and as old images become available and I catch them, I hit recreate and get the new image... but it would be easier if either I could tag the old image to recreate on next sign off or if the maintenance mode worked around the logged in users... it would make changes and updates less of a major undertaking.