Outlook "From" Button not working

For the Signatures issue this is probably expected due to migration to Roaming Signatures, Outlook roaming signatures - Microsoft Support. You may need to recreate the signatures. Any signatures that were not affiliated with accounts should be under the Account "Signatures on this device". The article I linked has more information about it.

Or, if you don't have time to deal with it you could use the policy key in that article to revert to the old behavior of signatures:

Path: HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Office\16.0\Outlook\Setup
DWORD: DisableRoamingSignatures​​​​​​
​​​​​​​Value: 1 

In case signatures stop syncing I posted a workaround in this forum thread, Outlook Signatures Not Appearing in Signatures and Stationery window - Microsoft Community. Its a bit of a sledgehammer but adding just in case.

I just updated this afternoon (around 3pm) to Build 16130.20332 and this update has resolved the issue! It also fixed a separate issue I was having with my signature.

Eddison, Martin,

The Outlook In App Team has gotten cases on this and they are investigating it. Please check if you can submit a ticket from Outlook by clicking Help, Contact Support.

If you are blocked, try the following:

1. Click on the Inbox of the account in Outlook you need to send email and click New Email.
2. Use web mail until we can get a fix or confirmed workaround

I will post back when we know more about the issue.

Any solution?

I have the same issue, All was working fine then the button just stopped working, like it is disabled.

Hi Eddison Cruz,

Good day! Thank you for posting to Microsoft Community. We are happy to assist you.

Based on your description, you cannot open the "From" button on an e-mail to change the sender's address.

Before proceeding, I may need to get more detailed information so that I can do some test from my side and better investigating on this issue, so please let me know:

1. Will you please share me your Outlook version details? Please follow this article What version of Outlook do I have? - Microsoft Support and follow the steps to check. You can also try to check is there is any update for Outlook, click File> Office account> Update options> update now.
2. Are you using Microsoft365 accounts or personal accounts (which is ended with outlook.com or hotmail.com) or some other 3rd party pop/imap accounts? Which protocol did you use to configure each account?
3. Please try to repair Office, Right click Windows button- Apps&features >find Office 365 >Modify >Repair. Check whether issue presists.
4. Did you get any error message when clicking on the "From" button? Wil you please share a screenshot of the view on clicking this button. Since the reply may contain some private information, kindly share via Private message:

Here are the steps to open private messages:

To view private messaging options> click your profile picture at the top on the right > select the My Profile option. Click View private message.

I look forward to your next update in private message for further analysis. Thank you very much for your cooperation.

Thanks for your precious time. Have a nice day！

Sincerely,

Sherry | Microsoft Community Moderator