Outlook 2016 Can No Longer Expand Distribution Group - + Plus Sign Missing - Looks Like Microsoft Recent Update

Question

Microsoft, in its infinite wisdom, appears to have removed the plus sign next to Microsoft Office 365 Group email addresses. I have a group called All that has all employees assigned to it. Before this week you could type in [email protected] in a new email message TO: field, and a plus sign would appear next to it. If clicked it would explode the distribution member email addresses into the TO: field which enabled group owners to remove certain addresses from receiving the email. This is now gone.

When I investigated this there is a new Group Settings under a Group tab in Outlook 2016 that appears when I click on an email in the inbox that was sent to a Group email address. I received a popup saying something to the effect of Check out our new Group Settings!

Does anybody have an answer for restoring this plus sign next to distribution group emails? I don't think there is one but I wanted to check.

I tried adding HKCU\Software\Policies\Microsoft\office\16.0\Outlook\Options\Mail
DWORD: DisableDLExpansion Value: 0 (1 is to hide the plus sign) but it made no difference.

You used to be able to do these steps below, which is no longer possible:

Expanding a Distribution List In order to see the members of a distribution list in Outlook, follow these steps:

1. Enter the lists's name into To, Cc, or Bcc field.

2. Click on Check Names icon on the ribbon or press Ctrl + K to validate list's name.

3. Click the plus sign (+) next to the name of the distribution list to show the list members.

Note: When you expand the list, the distribution list name is replaced with all the individual names on the list. You cannot collapse the list again in a message once it's been expanded.

Solution

Changing the group name, then changing it back in the Exchange Admin area appeared to be the reason it returned for this user.

The other change I tried but it didn't look like it helped was to create the DisableDLExpansion registry key, then delete it for Outlook 2016.

The DisableDLExpansion registry value is supported in Outlook 2007 and up. To use it in Outlook 2016, add the DisableDLExpansion DWORD to the registry at HKCU\Software\Policies\Microsoft\office\16.0\Outlook\Options\Mail\ and set the value to 1. For the other supported versions, change the version number in the registry path. As with moderated groups, users will be able to open the distribution group and view the members but will not be able to expand the list to bypass list controls.

Outlook 2016

HKCU\Software\Microsoft\Office\16.0\Outlook\Options\Mail
HKCU\Software\Policies\Microsoft\office\16.0\Outlook\Options\Mail
DWORD: DisableDLExpansion Value: 1

Outlook 2013

HKCU\Software\Microsoft\Office\15.0\Outlook\Options\Mail
HKCU\Software\Policies\Microsoft\office\15.0\Outlook\Options\Mail
DWORD: DisableDLExpansion Value: 1

Outlook 2010

HKCU\Software\Microsoft\Office\14.0\Outlook\Options\Mail
HKCU\Software\Policies\Microsoft\office\14.0\Outlook\Options\Mail
DWORD: DisableDLExpansion Value: 1

Outlook 2007

HKCU\Software\Microsoft\Office\12.0\Outlook\Options\Mail
HKCU\Software\Policies\Microsoft\office\12.0\Outlook\Options\Mail
DWORD: DisableDLExpansion Value: 1

Comments

[ComputerGiant]

Thanks for verifying this. I found that renaming the distribution goup then reverting the name seemed to fix the issue.

[ComputerGiant]

Had the same user experience the loss of the plus sign again, and changing the name of the group then changing it back restored the functionality overnight.