#outlook
← All tagsOutlook is the dominant email client in Microsoft 365 organisations, but its signature management is designed for individuals, not organisations. Each installation stores signature data locally, with no native sync across devices. The transition from classic Outlook (COM add-ins) to new Outlook for Windows (Office.js add-ins) is creating compatibility issues for organisations whose signature tools rely on the older model.
- How to Stop Employees Changing Their Signature in Outlook You sent everyone a signature template and people still edit it. Here's what Microsoft 365 offers to lock it down — and why neither option is a clean answer.
- The Best Email Signature Designs for 2026 Most email signature design galleries show layouts that break the moment they hit Outlook. Five archetypes that actually render, and what sinks the rest.
- How to Set Up a Company-Wide Email Signature in Microsoft 365 A step-by-step guide to applying one email signature to every employee in Microsoft 365 — mail flow rules, personalisation tokens, limitations, alternatives.
- New Outlook for Windows and Email Signatures Classic Outlook and new Outlook use incompatible add-in models. If your signature tool relies on a COM add-in, it will not work after migration.
- WiseStamp Alternatives for Business Teams (2026) WiseStamp's browser-extension model is increasingly blocked by IT, and its focus narrowed since the vCita acquisition. Here's what business teams need instead.
- Exclaimer Alternatives: An Honest Comparison (2026) Looking for Exclaimer alternatives? Compare CodeTwo, Letsignit, Rocketseed and WiseStamp on pricing, deployment models, and who each tool actually suits.
- Signature Management for Microsoft 365: Server-Side vs Add-In Server-side and add-in email signature tools differ significantly on GDPR, mobile support, and the compose experience. What IT admins need to know.
- Centralised Email Signatures in Microsoft 365: Complete Guide Everything IT admins need to know about centralised email signatures in Microsoft 365 — native options, their limits, and how third-party tools compare.
- How to Manage Email Signatures Across a Company Standardising company email signatures? This guide maps deployment options, technical tradeoffs, and questions to ask before choosing a tool.
- Why Designing HTML Emails for Outlook Is Still a Nightmare Outlook HTML email rendering was broken by design — here's why the Word engine ruined everything in 2007, what still breaks in 2026, and how to code around it.
Further reading
- Outlook add-ins overview — Microsoft Learn Overview of the Office.js add-in platform, the model used by modern email signature tools in both classic and new Outlook.
- Centralised Deployment for Office Add-ins — Microsoft Learn How IT admins deploy and manage Outlook add-ins across a Microsoft 365 tenant from the admin centre.
Frequently asked questions
Why don't signatures set in Outlook sync across devices automatically?
Outlook's signature feature is designed for individual users and stores signature data locally on each device. There is no native Microsoft 365 mechanism to sync signatures across Outlook installations on different devices or operating systems. An employee who sets up a signature on their Windows laptop will not automatically have the same signature on their Mac or iPhone. Central management tools solve this by applying signatures at either the add-in or server level, independently of the device.
What is the difference between a user-set Outlook signature and one applied by a management tool?
A user-set Outlook signature is stored locally on the device and can be edited by the user at any time. A signature applied by a management tool is either injected by an Outlook add-in — visible in the compose window but managed centrally and not editable by the user — or appended server-side after the email is sent, which means it is not visible during composition. The management tool approach enforces a consistent standard and removes the individual as a variable.
Does the new Outlook for Windows support the same email signature add-ins as classic Outlook?
No. The new Outlook for Windows uses the Office.js web add-in platform, which is incompatible with COM add-ins used by classic Outlook. If your email signature tool is built as a COM add-in, it will not work after users switch to the new Outlook. Tools built on Office.js are compatible with both, and are deployed via Microsoft Centralised Deployment or the Microsoft AppSource marketplace. Checking which model your current tool uses is an important step before any Outlook migration.