Outlook for Mac v16.108 - Can't Select Signature for New Messages

ehabrams133 0 Reputation points
2026-04-17T15:43:27.46+00:00

Newest version of Outlook for Mac 16.108 (04.17.2026) - I am unable to select a default signature 'For new messages' or 'For replies or forwards' and save the setting. Each time I close the settings window it reverts back to 'None' default selection.

How can I include my standard signature in all new messages without manually adding them each time I compose a new message??

Outlook | MacOS | New Outlook for Mac | For business
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  1. AI answer

    2026-04-17T15:43:41.3033333+00:00

    This behavior is not expected; Outlook for Mac supports setting a default signature for new messages and for replies/forwards per account. Use the built‑in signature settings and, if needed, re‑set them after updating Outlook.

    Try the following steps in new Outlook for Mac 16.108:

    1. On the Outlook menu, select Settings.
    2. Under Email, select Signatures.
    3. Under Choose default signature, select the mail account that should use the signature.
    4. For New messages, choose the desired signature instead of None.
    5. For Replies/forwards, choose the desired signature instead of None.
    6. Close the Signatures window to save the settings.

    If the setting still reverts to None after closing:

    1. Make sure Outlook is updated to the latest build (there was a recent build‑to‑build fix for signature issues in the 16.108 range).
    2. Reopen Outlook > Settings > Signatures and re‑apply the default signature for the account as above.
    3. Test by composing a new message and a reply to confirm the signature is inserted automatically.

    If the problem persists even on the latest 16.108+ build, this indicates a product issue rather than configuration. In that case, use manual insertion as a temporary workaround (Message > Signature > select signature) and contact Microsoft support or your Microsoft 365 admin so they can capture logs and escalate, referencing that default signature choices are not being persisted for the account in Outlook for Mac 16.108.

    References:

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  2. Hin-V 16,830 Reputation points Microsoft External Staff Moderator
    2026-04-17T16:26:59.48+00:00

    Hi @ehabrams133

    Thank you for sharing your concerns.  

    I understand that you are experiencing an issue where your custom signature cannot be set as the default in New Outlook for Mac. 

    I have tested this behavior on the same version you are using (Outlook for Mac version 16.108), and it is working as expected on my end. 

    image

    You could try to follow the steps below to configure the default signature: 

    Open Outlook and select New Mail. 

    Click Signatures on the toolbar, then select Manage Signatures. 

    Choose your custom signature. 

    Under Set default signatures, please ensure that: 

    Select the correct email account you want to apply the signature to. Then, assign the appropriate signature for "For new messages" and "For replies or forwards". 

    Note: If the account is missing or if another account is selected by mistake, the signature may not be set correctly. 

    Once completed, fully close the Outlook application, reopen it, and test again to see if the issue persists 

    Please understand that our initial reply may not always immediately resolve the issue. However, with your help and more detailed information, we can work together to find a solution. 

    Note: Please follow the steps in [our documentation] to enable e-mail notifications if you want to receive the related email notification for this thread. 

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  3. D Michael Enfield 0 Reputation points
    2026-09-14T02:23:33.6466667+00:00

    There is a simple issue that affects many people who can't get Legacy Outlook for the Mac to maintain correct designated signatures for different email accounts. Accessing the Edit Signatures window, either through Outlook>Settings>Email>Signatures, or by clicking on Signatures>Edit Signatures in the menu bar of any open email message (the resultant window is identical regardless of which way you access it), many people instinctively click on their account names in the left-hand column under Signature Name, and then move down to the toggle bars at the bottom of the window for Accounts, New Messages, and Replies/Forwards, setting each of those for their different accounts. Then after having done the same thing for two or more of their accounts, they discover that, after then looking back at each one, the choices they have made have changed, most typically with each account winding up with the same account name - the one separately selected as the Outlook Default Account established in the main Outlook menu under Tools>Accounts, or the wrong New Messages, and Replies/Forwards settings, or likely all three. The reason for this is that attempting to assign default preferences by clicking on the Account names in the left-hand column is an improper procedure for assigning defaults, and will never work, even though it seems intuitive to do it that way. The only way it can be done correctly is by avoiding any selection under Signature Names, and instead making all of the default selections in the three toggle bars at the bottom, under Choose default signature, whether accessed through Outlook Settings or via the Edit Signatures button in any open email message Menu bar**.**

    Many people presume that there is a bug in Outlook, when really it's simply a matter of inadequate instructions.

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    1 person found this answer helpful.
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