After installing Adobe Acrobat, I, like many others, started getting “A program is trying to access your Address Book…” message every time I created a new mail item.  Luckily, many people prior to me have come across same issue and provided recommendations on how to resolve it.  However, not one of them (that I saw) explained the reason behind the problem and the resolution.  So, this blog post is my attempt to do just that.

 

So, the solution offered is to change LoadBehavior registry key under HKEY_LOCAL_MACHINE\Software\Microsoft\Office\Outlook\Addins\PDFMOutlook.PDFMOutlook from 3 to 2 (some suggested to change it to 0).

 

First, there is no reason to mess with the registry directly.  In Outlook, go to Tools -> Options -> Other tab -> Advanced Options -> COM Add-Ins and imply remove the add-in from there.  This is a safer recommendation for end users…

 

Now, what exactly does it do?  HKEY_LOCAL_MACHINE\Software\Microsoft\Office\Outlook\Addins\<add-in name> LoadBehavior registry value specifies the way the COM add-in should be loaded. The value can be a combination of 0, 1, 2, 8, and 16:

 

0 = Disconnected. The add-in is shown as not connected in the Add-in Manager.

1 = Connected. The add-in is shown as being connected in the Add-in Manager.

2 = Load at Startup.

8 = Load on Demand. The add-in will be loaded and connected when the host application requires it, e.g., when a user clicks on a button that uses functionality in the add-in.

16 = Connect first time. The add-in will be loaded and connected the first time the user runs the host application after registering the add-in.

 

So, by setting the LoadBehavior value to 2 (a.k.a. “soft disabling”), the Adobe toolbar will not be loaded (thus, no annoying popup message).  If an add-in is soft-disabled, the user can re-enable it by using the Office COM Add-ins dialog box. If the add-in is hard-disabled, the user can attempt to re-enable it by using the Office Disabled Items dialog box.

 

Reference: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/odc_ol2003_bk/html/OfficeProgrammingOutlookExchangeCh7.asp