Signatures not injecting in large threads

Question

Signatures not injecting in large threads

Abram Botterill 0

I am using a third party signature management system (WiseStamp). When replying to a very large email thread the Outlook Add-in doesn't auto-inject the signature, and even when opening the side panel and clicking on the name of the signature it won't manually inject the signature.

I ran the diagnostics for this in Outlook on Mac and was given the Incident ID 7h09gA

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Answer 1

Hendrix 1,670 Independent Advisor

Hi Abram,

Because WiseStamp is a third-party Outlook add-in, I first need to determine whether the issue is specific to WiseStamp, Outlook for Mac, or the size and complexity of the email thread. Therefore, can you please give more details about the situation? I greatly appreciate your cooperation and understanding.

Does the signature insert correctly when replying to a new or short email thread?
Does the same large thread show the issue in Outlook on the web?
Does the issue affect every large thread or only one particular conversation?
What Outlook for Mac version and macOS version are you using?
Does creating a new message and copying only the latest required content into it allow the signature to be inserted?
Please also update Outlook and the WiseStamp add-in, restart Outlook, and test again.

I want to ensure I have a clear understanding of the situation to provide appropriate guidance. Should you have any questions, please feel free to reach out again in the comments on this post. I'm happy to help.

Abram Botterill 0 Reputation points

2026-09-29T13:36:27.2533333+00:00

Hi @Hendrix ,

When using a local default signature then it injects correctly with no issue. But when using WiseStamp on very long thread the signature isn't auto or manually injected. This issue cannot be reproduced with smaller email threads. If copying the last reply to a new email then the signature auto-injects into the body.

Mac Version: Tahoe 26.5.2
Outlook Version: 16.113.2 (26092012)
Hendrix 1,670 Reputation points Independent Advisor

2026-09-29T16:18:26.5933333+00:00
Hi Abram,

Thank you for the information. Based on what you shared:

Outlook’s local signature inserts correctly

The WiseStamp signature works in new messages and shorter threads.

Both automatic and manual WiseStamp insertion fail only in very long threads.

Copying the latest reply into a new message allows WiseStamp to insert the signature.

This indicates that Outlook’s signature editor is functioning, and the WiseStamp add-in is installed and generally operational. The issue appears to be triggered by the size or complexity of the conversation body when the WiseStamp add-in attempts to process it.

Therefore, I suggest testing in Outlook on the web:

Sign in at https://outlook.office.com and open the same long conversation.

Select Reply > check whether WiseStamp inserts the signature automatically.

If not, open the WiseStamp panel and insert it manually.

If the same problem occurs in Outlook on the web, please report it to WiseStamp Support, since it indicates the add-in cannot process a particular message body or a thread above a certain size. If the signature works in Outlook on the web but fails in Outlook for Mac, the next step is to contact Microsoft 365 Support.

Please give it a try and let me know what is the outcome.
Hendrix 1,670 Reputation points Independent Advisor

2026-09-30T22:57:12.2933333+00:00

Good day Abram,

How are things going? Any updates would be appreciated.