If you have end users running Outlook 2003 then you may have been asked about how to help them with a Reading Pane question. Sometimes it will appear that the preview pane takes longer than expected to populate with the contents of an email.

This long delay often happens with Outlook 2003 after an end user has received or clicked an encrypted email message. After clicking on the email message the preview pane pops up but is never populated and appears unresponsive to mouse clicks. And Outlook itself stops responding to user clicks. After the long delay a message appears in the preview pane which reads:

“This item cannot be displayed in the Reading Pane. Open the item to read its contents.”

There is a hotfix available from Microsoft for this error. The hotfix is in the Outlook 2003 post-Service Pack 3 Hotfix Package. More information can be found in the Microsoft Knowledge Base article 935411. Once the hotfix is applied an administrator will have to add the “DisableEncryptedMessagePreview” entry to the registry.

To enable the hotfix changes will need to be made to the registry. As always, before making any changes to the registry please be sure to back up the registry first. As long as you have a working backup of the registry you will be able to restore to a known working state should any problems or mistakes happen while making changes to the registry. An administrator should always be the first person of choice to make registry edits.

After a backup has been made and before any changes are made Outlook should be exited. Then proceed to bring up the Registry Editor on Windows. This can be done by clicking on the Start button and then clicking on the Run option. This will bring up a popup box where you can type “regedit” into the text field and then hit Enter.

Some systems may prompt you for an administrator password or a confirmation. Here the administrator will need to type in the password or click Continue.

The following steps should be followed to enable the hotfix:

1. Locate and then click on the following registry subkey: HKEY_CURRENT_USERSoftwareMicrosoftOffice11.0OutlookOptionsMail
2. From the Edit menu, point to New and then click the “DWORD Value”.
3. Type in DisableEncryptedMessagePreview and press ENTER.
4. Right-click DisableEncryptedMessagePreview, and then click Modify.
5. In the Value data box, type 1, and then click OK.
6. On the File menu, click Exit to exit Registry Editor.

Without the hotfix package installed, Outlook will open the encrypted email message internally. This may take a very long time to open the email especially if the email message contains a large attachment or a large amount of text in the body of the message. Next, Outlook will check to see if the email message is encrypted. If so, then this is when your end user will receive the message:

“This item cannot be displayed in the Reading Pane. Open the item to read its contents.”

What the hotfix package changes is the sequence of loading, opening and then checking for encryption. With the hotfix installed, Outlook will first check to see if the email message contents are encrypted before loading the message into memory. The hotfix shortens the amount of time it takes Outlook to load a large attachment or an email with a large amount of text in the body of the email. Upon finding an encrypted email message Outlook will display a different message in the preview pane:

“This encrypted e-mail cannot be displayed in the Reading Pane. Open the message to read it.”

Now if you want to completely disable the Preview Pane functionality in Outlook then an administrator can add the following change to the registry:
HKEY_CURRENT_USERSoftwarePoliciesMicrosoftOffice9.0OutlookDisabledCmdBarItemsList
Valuename: TC1D1
Valuetype: String
Value: 5514

Another way for an administrator to turn off the Preview pane – if using Outlook 2000 – is by following the steps listed below:

1. Click the Start button and then click on the Run option.
2. Type “regedit” and then click OK or hit enter to bring up the Registry Editor.
3. Locate the following registry key: HKEY_CLASSES_ROOTCLSID{00020D75-0000-0000-C000-000000000046}ShellOpenCommand
4. In the right pane, right-click Default, and then click Modify.
5. Type the path for your Outlook.exe file with the /nopreview switch in the Edit String dialog box, and then click OK or hit enter. Such a command will look like:

“C:Program FilesMicrosoft OfficeOFFICEOutlook.exe”/nopreview

Then exit out of the registry and restart Outlook. You’ll now be able to run Outlook without getting preview errors.