"Received PURGED_MESSAGE_LIST from device for user not enabled for purged message list processing"

will be the error you are going to get if it is the issue with large amounts of purged email and that causes the inbox to not be selected, as far as I can tell. ( I could be wrong) this is causing the issue with the inbox being turned off. Therefor, if you see this, the user's inbox will be un selected. If you don't see if, they are not having an issue.

If you know of a user who had the issue, go through the logs before you had to fix the user and you should see this log line.

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MCSA 2003 +M MCITP | EMA
Who cares, RIM will just change how they do Cert's again