Sending Categories on Email Messages

Last reviewed on January 25, 2015   —  30 comments

To avoid releasing potentially private information on outgoing email messages, categories are not sent with email in Outlook 2003 and up when you use Exchange server mailboxes. When you use categories with internal codes or potentially embarrassing keywords, the recipient will not see them.

This does not apply to POP3 or IMAP accounts. The Category is removed by Exchange Server’s transport rules, not Outlook, when the message is sent. A rule in Outlook 2007 and 2010 removes categories as messages are downloaded; Outlook 2013 does not have this rule, users will need to create the rule to remove categories.

If you need to send categories on outgoing email you can use the SendPersonalCategories registry entry.

Warning: when making this change, the categories will be included on the sent message and the recipient will be able to see the category (unless the recipient uses a rule to remove categories from messages they receive).

Create the key or path if it does not exist. This key should take effect without restarting Outlook.

In Outlook 2013 RTM, the SendPersonalCategories key does not work. The Category is kept on Sent Items in your mailbox only. It’s fixed in a later update.

Outlook 2013

DWORD: SendPersonalCategories
Value Data: 1 to keep categories on sent mail, 0 to not include categories

Outlook 2010

DWORD: SendPersonalCategories
Value Data: 1 to keep categories on sent mail, 0 to not include categories

Outlook 2007

DWORD: SendPersonalCategories
Value Data: 1 to keep categories on sent mail, 0 to not include categories

Outlook 2003

DWORD: SendPersonalCategories
Value Data: 1 to keep categories on sent mail, 0 to not include categories

If you setting the SendPersonalCategories value, users can still delete the categories as messages arrive by using a rule.

Do it for me

If you don’t want to edit the registry yourself, you can download and run a registry file to make the changes. This reg file also sets AcceptCategories value.

Outlook 2013Outlook 2010Outlook 20072003

Default Rule to Remove Categories

Outlook 2007 and up have a default rule that removes categories from messages as they arrive. Delete the rule or disable it if you want to keep the categories.

Outlook's default rule to remove categories

Remove Categories using a Macro

If categories are being sent, you can use a macro to remove the categories as the message is sent. Place the macro into ThisOutlookSession.

Private Sub Application_ItemSend(ByVal Item As Object, Cancel As Boolean)
Item.Categories = ""
End Sub

Exchange rule to remove categories

In Exchange 2007 and up, categories are removed from messages. To disable it, the administrator can use this cmdlet to change the transport setting.

Set-transportconfig -clearcategories $false

Other methods

If you need to include the category on a one time basis, drag the item to the hard drive, zip it and email the zip file. The recipient will drag the item to a folder in their Outlook and if using Outlook 2007, can add the categories to their master list by using the Upgrade to color categories option in the root folder properties.

Add Categories to Master list

In Outlook 2007 or 2010, to add a category that is not in your master list, to your master list, select it (so its highlighted) and click the New button.

Not in master list

Outlook will assign the next unused color – change the color and set a shortcut key, if desired, then click Save.

Adding Categories when Composing Email

The Categories button is not available when you are composing new messages. When you need to assign categories, you need to add the category to the message either in the Sent folder or in the Outbox.

To add the category before hitting Send, you can use VBA to open the Categories dialog. Add the following code to the VB Editor and then add a button to the QAT, Ribbon, or Toolbar of a message form. Click the button to open the Category dialog.

'by Michael Bauer
Public Sub ShowCategoriesDialog()
  Dim Mail As Object
  Set Mail = Application.ActiveInspector.CurrentItem
End Sub

More Information

Outlook Categories (Slipstick)
More Category VBA Code Samples by Michael Bauer:
E-Mail: Categorizer for outgoing e-mails
E-Mail: Categorize and move

About Diane Poremsky

Diane Poremsky
A Microsoft Outlook Most Valuable Professional (MVP) since 1999, Diane is the author of several books, including Outlook 2013 Absolute Beginners Book. She also created video training CDs and online training classes for Microsoft Outlook. You can find her helping people online in Outlook Forums as well as in the Microsoft Answers and TechNet forums.

Please post long or more complicated questions at Outlook forums by

30 responses to “Sending Categories on Email Messages”

  1. Rick Medford (@rickmedford)

    Any idea how to stop Outlook 2013 from stripping the categories on outgoing mail?

    1. Diane Poremsky

      Did you try the key? It should work on 2013 too. Okay, so it looks like the key does not work. I'll check on it because it is the only way to keep categories, short of sending messages in an attached zip file.

    2. Diane Poremsky

      Are you using Exchange server? The server may be stripping them - once I remembered the default is to strip categories, I ran the cmdlet to keep categories and the key works in 2013. If neither the sending nor receiving system in Exchange, categories *should* stick with that key set.

      Set-transportconfig -clearcategories $false

  2. Rick Medford (@rickmedford)

    I'll see if the Exchange server is the problem and report back. Thanks.

  3. Rick Medford (@rickmedford)

    Bingo! That did the trick. Thanks for you help.

  4. jacopo3001

    I am in an Exchange environment, configured by IT.
    When I send emails, my recipients get to see my categories!

    How can I avoid this? I don't want my colleague to see my way of organizing emails

    1. Diane Poremsky

      Check the registry at HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\xx.0\Outlook\Preferences (xx = your version of Outlook) for a key named SendPersonalCategories. It should either not exist or be set to 0. If it exists and is set to 1, speak to your Exchange admin and ask them to change it.

  5. Ian Slater

    When the mail is answered will the categories still exist in my inbox? Or are they dependent on the recipients set up?

    1. Diane Poremsky

      it's dependent on the recipients set up. however, if you use outlook 2010/2013 with conversations enabled, you should see the category of your original message and can add it to the reply.

  6. Ian Slater

    thanks, Diane.

  7. Alex K

    Hi Diane,

    I see Outlook 2013 sending categories to the recipient even when SendPersonalCategories is not set. Users are concerned about data leak. More details about here:

    Do you have any ideas why this is happening and how to fix it?

    Thank you!

    1. Diane Poremsky

      I'll have to look into it. it *should* work and if it doesn't, then it's a bug.

    2. Diane Poremsky

      BTW, what is your build number? I'll check in both older builds and SP1. The moderator in that forum post is probably using SP1.

  8. Alex K

    First line of the About window:
    Microsoft Outlook 2013 (15.0.4551.1511) MSO (15.0.4551.1508) 64-bit.

    I really appreciate you looking into this, Diane.

    1. Diane Poremsky

      Thanks. That is the last pre-SP1 build. I'm assuming you are using a subscription version so it won't be updated for about 2 weeks (assuming i can repro the bug in that build and not in SP1.)

  9. Alex K

    Hi Diane,

    According to the last reply from a Microsoft employee, the fact that recipient sees categories is expected. As you say in this article, this creates a private data leak risk. Users have an expectation that the categories they assign are seen only by them. Your article (and other similar posts) confirm it.

    What are your thoughts on this?

    Thank you!

    1. Diane Poremsky

      I haven't had a chance to test it yet - I do have the key set and can send categories. Make sure you check for the key, both in the regular location and also in HKEY_CURRENT_USER\Software\Policies\Microsoft\office\15.0\outlook\preferences - I recommend deleting it, rather than changing it to 0.

    2. Diane Poremsky

      download and run this reg file - - it will delete the keys if they are in your registry. Restart outlook and see if you are still sending the category.

      ETA: I testedi t here and I'm not sending categories unless the key is set.

    3. Diane Poremsky

      Actually, after sleeping on it... I think the bug is that Outlook 2013 doesn't create the 'delete categories' rule for incoming mail, which it does in 2003, 2007 and 2010. This removes the categories. Exchange server also removes the categories - at the transport level - but Outlook doesn't have the capability to remove categories from mail as its being sent and leave it on the message. Without the rule (and to insure recipients can't see the category) you need to use an addin or a macro to categorize sent messages.

    4. Diane Poremsky

      One more comment, I promise - see categories on this page for a note about it.

  10. Alex K

    Having a rule to strip categories on incoming messages does not protect from information leak :(

    And judging from what the page you linked says, the leak is actually "by design". "Be very careful about categorizing your outgoing messages — your recipients might be able to see your categories". This is unfortunate.

    Diane, thank you so much for getting to the bottom of it! At least now it is clear that Outlook is not stripping categories which as assigned before a message is sent, unless sender is using Exchange.

    1. Diane Poremsky

      No, it doesn't prevent PII leakage. The mvps discussed it this morning and had some of the same confusion we had last night. I don't know if some of the information was lost when the site was moved into the wordpress but I'll make it more clean since more people will notice this problem since the rule is no longer added by default - that hid the problem from many users.

  11. Cameron Robinson

    I cannot seem to get this to work for Outlook in Office 365 using the Office 365 Email server. HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\15.0\Outlook\Preferences does not exist. Only HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\15.0\Outlook\Security

    1. Diane Poremsky

      if a key doesn't exist, you need to create it. right click on the Outlook key and choose New>

    2. Cameron Robinson

      I created the key but it had not affect.

    3. Diane Poremsky

      Did you restart Outlook? What version of Outlook do you use? Did you type the key in or use the reg files I included?

  12. Cam Robinson

    Yes, I restarted Outlook. I am using Office 365 which I believe is the latest version of Outlook. I did it twice. First manually and then with the reg files.

    1. Diane Poremsky

      Offhand, I don't know why its not working for you. It should (and does here). Sorry.

  13. Cam Robinson

    I am using the 64 bit version of office - I am not sure if that makes a difference.

    1. Diane Poremsky

      No, the bitness wouldn't affect this.

Leave a Reply

If the Post Comment button disappears, press your Tab key.

This site uses XenWord.