Just a cautionary post. I didn't see any forum posts or TIDs about this, so here's what happened to me and how I fixed it.

We're having an issue where deploying the 10.3.3 agent is taking a long time to update, only a few dozen a day and only about 900 workstations. We have a gigabit fiber WAN so that's not an issue.

So when we have to fix machines for one thing or another we manually update the agent to 10.3.3. We only do the local uninstall of the agent. I decided to leave CASA behind; consequently, after installing the new agent, users could no longer log into the agent. A Windows error message said something like, "Unable to log in to network, login credentials are incorrect."

Locally uninstalling the agent AND CASA, then reinstalling the new agent worked just fine.