Last week, I headed out to collect inventory for a local business who recently enlisted the help of our consulting department. While I went around from machine to machine capturing System Profiler information, I also asked each user if he or she was experiencing any issues.

If the issues were reasonably simple, I attempted to fix them on the spot, while the bigger issues were to be explored during the inventory review. One user had an issue with her Entourage application that really piqued my interest.

For those who don’t know, Entourage is Microsoft’s equivalent of Outlook for the Mac, at least until “Outlook for Mac” comes out with the 2010 version of Microsoft Office being released later this year. The client I’m working for hosts her email services on an Exchange Server, and this particular user is used to getting her mail in her Exchange Inbox. However, since the previous Friday (about four days before my visit), she was receiving both incoming and sent mail into her local Inbox. Bizarre!

The user stated that she had not run any updates on her machine; she had no idea how the change occurred, though someone was “helping” her with her machine around the time the issue occurred. I verified, by sending myself an email from her account, that indeed, both the message she sent me and my reply to her appeared in her local inbox.

I checked the Exchange account directly through the company’s webmail and verified that the messages in the local inbox were not syncing with the Exchange server. Then, I verified she only had the one account set up in Entourage. This continued to be quite strange.

I started with some additional basic troubleshooting. First, I tried moving her Entourage preference file (/Users/youruser/Library/Preferences/com.microsoft.Entourage.plist) to the Desktop so that a new preference file would be created when the program was launched; this did not resolve her issue.

Next, after restoring the original preference file, I backed up and then rebuilt her database using the Microsoft Database Utility (/Applications/Microsoft Office 2008/Office/Microsoft Database Utility). When this failed, I deleted her Exchange account and re-added it; alas, this also did not resolve the issue either.

When the usual fixes didn’t work, I hit my favorite research tool: Google. I sifted through discussion boards with an appropriate amount of salt (let’s face it, for most of those discussion boards, one needs an entire salt shaker) and lo and behold I found several users reporting similar issues.

All signs pointed towards a corrupt or incorrect rule setup in Mailing List Manager. I headed to Entourage and then to Tools > Mailing List Manager, and sure enough, there was a rule set up in there. What made things hit a little close to home is that the rule was named “Small Dog.” OK, things just got weirder.

I opened up the “Small Dog” rule and it included a string that looked similar to a URL mixed with other random text. What was more interesting was finding what the rule did—it was set to put all incoming and sent messages in the local Inbox. Mystery solved!

I questioned the user about the rule and she admitted that she was attempting to unsubscribe from our Kibbles & Bytes newsletter on Friday (the day her issue occurred) but may have done it incorrectly. I deleted the rule and properly unsubscribed her from the newsletter by clicking the “unsubscribe” link at the bottom of the email (I didn’t check to see if she was subscribed to Tech Tails!).

Voila! All incoming mail was going into the proper Exchange inbox (and syncing with the server) and all sent mail was back in the proper sent folder.

Once I was back at my desk, I did a little more digging to see if somehow we had a bad link in our HTML edition of the newsletter that could have somehow created a rule in Entourage. I clicked my little heart out and all of the links worked as expected.

After playing around a bit more, I found that if one marks an email as Junk in Entourage and then marks it as not junk a pop-up appears with three options. One of the options is to create a Mailing List Rule. Apparently, this user (or the person helping her) had chosen that option and attempted to set up a rule for the newsletter instead of just unsubscribing from it. Since the rule was set up incorrectly, it caused frustrating and bizarre issues for the user.

The moral of the story is that rules can be fickle things and it’s important to really think them through before setting them up. I remember the first time I ever created a rule years ago in Mail.app, one that sent a “vacation auto-reply” to people who wrote to me, it ended up automatically sending the message to everyone in my inbox, spamming years of contacts. D’oh! So, be careful with your rules and if something goes wonky right after setting up a rule, it’s best to delete it and start again. Good luck!