Force all emails to be received or shown in Plain Text

Outlook has a security setting to force all emails to show in Plain Text. This setting applies to all emails, even the ones that were already received.

When a message is being converted to Plain Text by Outlook, there will be an Infobar at the top of the message which reads:

”This message was converted to plain text.”

Click on this Infobar to convert the message back to HTML.

Trust Center Settings

The “Read al standard mail in plain text” setting can be found in the following location;

• Outlook 2007
  Tools-> Trust Center…-> E-mail Security-> Read all standard mail in plain text
• Outlook 2010 / 2013 / 2016 / 2019 / Office 365
  File-> Options-> Trust Center-> Trust Center Settings…-> E-mail Security-> Read all standard mail in plain text

Registry Setting

The above setting can also be set via the Registry by creating the ReadAsPlain value.

Key:
HKEY_CURRENT_USER\Software\Microsoft\Office\<version>\Outlook\Options\Mail
Value name: ReadAsPlain
Value Type: REG_DWORD
Value: 1

When this key is set to 0 or missing, all messages will display in their normal message format.

Note 1: If you are running a virus scanner that integrates with Outlook, you might also find an option there to convert all messages to Plain Text. Note that in most cases, this option works separate from the option set in Outlook. See the documentation of your security suite for more information.

Note 2: Administrators can also set this as a corporate policy.