Abnormally high Outlook 2010 RAM usage for one Terminal Server user (RDS)

I'm working on a busy Windows 2008R2 Terminal Server where a particular user's Outlook session consumes between 2GB and 4GB of RAM.

The process doesn't appear to be a slow memory leak, as the RAM is utilized almost immediately after the process opens.

To date I've tried the following:

• Logging into the user's session and checking out their Outlook settings. There's nothing abnormal. Default mail quotas are in place, the user only has 5,000 mailbox items. Quota is 3GB. User is using 1.2GB. Inbox is nearly empty. Deleted Items are pruned well.
• Outlook in Safe Mode. No difference.
• Removing Add-ins. No difference.
• Creating a new Outlook profile. No difference.
• Opening the user's mailbox from another account. No difference.
• Moving the user to a different terminal server. No change.

At this point, the user's Outlook RAM usage is 10x-20x that of any other user. Is there anything else I should look at?

Process information and stats via NewRelic:

Task Manager:

Process Explorer:

Edit:

VMMAP output:

After emptying "Working Set":

Solution 1:

I can't really explain why, but this issue only happens with a 64-bit edition of Outlook. Downgrading to 32-bit Outlook solves it.

Solution 2:

I had a user with a very similar issue years ago. The problem was caused by an external calendar. Try removing any/all external calendars.

In Outlook's Calendar Tab:

1. Record the URLs of any externally hosted calendars
2. Un-check the box next to any external calendar
3. Right-click each of those calendars and select "Delete Calendar"

Watch the memory footprint as you remove. If it drops significantly after removing one, you'll know the culprit. Simply re-add the calendars that play nicely.

I don't have sufficient reputation to leave comments yet, so I had to go Jeopardy-style and pose my question in the form of an answer... sorry if this is totally irrelevant.