MS provides us a way to disable the clutter feature via a simple cmdlet (https://blogs.office.com/2015/05/18/de-cluttering-everyones-inbox/) but if you have tried it, you have seen that the execution of the command is really long (from 7 sec to 15 sec in our case) and for a large number of mailboxes, it is a bit difficult to manage.

Also, you have no way to check if you already forced the turn off of the feature, the field “enabled” stay at false after execution of the command…

So to be sure that no email are moved to the clutter folder, you can setup a transport rule that will add the line “X-MS-Exchange-Organization-BypassClutter” with the value “true” and the effect will be that the message will not be moved to the clutter folder.

More information on the technet page : https://technet.microsoft.com/en-us/library/58e413f0-aa27-4307-bffd-4df03090a15e(v=exchg.150).aspx

An important thing, I wanted to add is that this line appear only on messages tagged by clutter. So you have to use MFCMapi to test the rule…