Recently, after installing Update Rollup 5 to several machines for a set of new users at a client, we noticed that they began to receive script errors every time they opened a contact record from a list within the client.  It looked a little something like this:

Naturally, we assumed culpability and began to review our code from all the other environments.  We studied the client side Web Resources we had in play, we varied the Security Roles set against the record, fields, and forms, we even looked at every registered plugin and ISV solution deployed.  We even turned on full trust in Outlook to allow all macros, scripts, etc.  One by one we turned them all off but the problem prevailed!

Our next level was to look at the client side trace file.  Sadly, it only led us to the get_WebBrowserExternalObject() function of the client with no distinct reference to the get_unselectedlds function from the actual error being thrown.

We still had the old uninstall/reinstall trick in our back pockets, so we performed our surgery and ripped everything out.  However, even after the failsafe trick, the error still persisted....

At this point we knew that the error was pointing to code that was not our own, so we pointed the Outlook client to a clean Out-of-the-Box Organization in CRM.  Guess what?!?!  The error still persisted!!!

Now that we knew the error was being produced by the native code of the Outlook client we knew our places to look would be even more limited.  After a short look, we found the answer.

If a user had personal options choosing any option other than to opt in for the Customer Experience Improvement program, the errors would appear.  However, as soon as we began sending them automatically to Microsoft, our client script errors went away!

I would suspect that in the next Update Rollup there will be a correction for this due to standard Opt in regulations, but for now, if your Outlook clients are producing this error, simply Opt In for the time being and they will subside....