Unable to set New Message signature

Question

I use code similar to the following VSTO C# to create Outlook Signatures:

var signature = WordApplication.EmailOptions.EmailSignature
signature.EmailSignatureEntries.Add("Signature Name", range);

I have multiple email accounts configured and the signature is created in "Signatures on this device" - not in any of the email accounts. Consequently, I can't manually set the "New messages" and "Replies/Forwards".

Can someone explain what is going on and how I can resolve my issue?

I think Microsoft may have broken this functionality.

I have been using the above code (for years now), to manage email signatures. However, things have changed in Outlook sometime in the last 6 to 12 months.

My colleague and I see different "Signatures and Stationery" dialogs. Even though we are both on Office 365 v2302 Build 16.0.16130.20186 64bit.

His dialog allows the "New Messages" signature to be set. Mine does not.

The main difference I can see between our computers is that I am on Windows 11 whereas he is on Windows 10. We both have multiple email accounts configured within Outlook. I have a "Signatures on this device" option. He does not.

From my computer where the dialog DOESN'T work:

From his computer where the dialog DOES work:

Answer 1

With thanks to Christopher Edwards

https://answers.microsoft.com/en-us/outlook_com/forum/all/unable-to-set-new-message-signature/66174399-4ab9-4c15-9c88-d0f1a7550a64?messageId=3a75ef23-35f6-4446-8a5a-52e7dc38223f

I am actually using VBA and I have actually seen the same thing and I believe it is related to the Roaming Signatures feature that has now been rolled to 50% of Outlook 365 Desktops in the current build.. https://www.microsoft.com/en-us/microsoft-365/roadmap?filters=&searchterms=60371 There is also a reg fix at the top of this thread - https://techcommunity.microsoft.com/t5/outlook/outlook-roaming-signature-vs-signatures-on-this-device/m-p/3672866 More details here - https://support.microsoft.com/en-us/office/outlook-roaming-signatures-420c2995-1f57-4291-9004-8f6f97c54d15?ui=en-us&rs=en-us&ad=us