So apparently others have stumbled upon this but when doing my rebuild of RTM over the weekend I noticed a nifty little error popping up in the event log that raised a little concern with regard to the TaxonomyPicker user control.

Looking at the error, you’ll notice that it states the TaxonomyPicker.ascx user control can’t register an assembly ‘Microsoft.SharePoint.Portal.WebControls.TaxonomyPicker’ from assembly ‘Microsoft.SharePoint.Portal, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c’.

If you’ve seen something like this before it’s typically because either a user control was edited incorrectly such that a character was incorrectly added to the assembly register string, or someone removed the assembly from the server and the user control is “freaking out” (never a good thing).  In this case it’s just a typo in the user control – but wait, this is out of the release to manufacturing right? Yeah, about that…

So the fix, simply navigate to the 14 root at: %systemroot%\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\CONTROLTEMPLATES where you’ll find the TaxonomyPicker.ascx user control.

If you haven’t created a short cut to the 14 root yet, you may want to as I’m sure you’ll be visiting there often

First – make a copy of the file and save it as perhaps TaxonomyPicker.ascx_backup or something along those lines – what works for you, run with it.

Next using your favourite text editor (TextPad for me), open the user control and observe in the first line the error.

Interesting that “TaxonomyPicker,” made it through quality assurance testing, but alas, not a huge detail right? Simply replace the “,” with a “,”

Save the user control and restart the app pool and presto, the error should be no more.

Permissions still as they should be? Should look like this…

Also, check to ensure that you’re still inheriting permissions properly by opening the file properties -> security -> advanced

And with that, you’re done. Happy tuning.

Update – Apparently the error will continue to persist even after making the correction to the file.

Looking in the Microsoft.SharePoint.Portal Assembly it looks like there is no actual TaxonomyPicker class, so in reality you can just keep the copied file (TaxonomyPicker.ascx_broken) and remove the fixed version. That being said, until the TaxonomyPicker class is implemented within the Microsoft.SharePoint.Portal assembly, you’re safe in not worrying about this user control.