Blocking / Locking or Unlocking pst files in Outlook

Blocking or removing

Set the value of each of the following registry keys to 0 (block) 1 (enable):

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12\Outlook\Preferences\ArchiveDelete
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12\Outlook\Preferences\ArchiveMount
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12\Outlook\Preferences\ArchiveOld
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12\Outlook\Preferences\DeleteExpired
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12\Outlook\Preferences\DoAging
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12\Outlook\Preferences\PromptForAging

Now we're going to disable the use of .PST files on users' workstations. To do so, the administrative template for Microsoft Outlook must be installed.

Open the Group Policy Object Editor and navigate through the group policy tree to: User Configuration -> Administrative Templates -> Microsoft Office Outlook 2007 -> Miscellaneous -> PST Settings.

I recommend verifying that the group policy setting Prevent Users From Adding New Content to Existing .PST Files is still enabled. Next, enable the Prevent Users From Adding .PSTs to Outlook Profiles and/or Prevent Using Sharing-Exclusive PSTs.

When you enable this setting, you need to decide which setting you want to use. The default setting lets users continue to add .PST files. Therefore, simply enabling the policy setting doesn't help reach our goal.

The next option is to disallow the addition of .PST files. While this may seem like the best option, it does have some nasty side effects. If you block all .PST files, then some Microsoft Outlook features, such as SharePoint lists and Internet calendars, will cease to function.

The final option is to add only sharing-exclusive .PSTs. This is usually your best option because it prevents users from copying mail items to and from .PST files. It also won't prevent certain Outlook features from working.

I prefer to use the Group Policy Object Editor to lock down .PST files. However, some Exchange administrators prefer to use a registry setting that removes the Outlook Data File option from the menu when a user selects the New command from Outlook's File menu. If you want to try this approach, go to the following registry key and set its value to 5575:
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12\Outlook\DisableCmdBarItemsList\TCID1

Create Unlock.reg file and run as follows (example Remove Block):

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Outlook\Preferences]
"DoAging"=dword:00000001