Email signatures after a merger or tenant migration
Two companies, two brands and often two Microsoft 365 tenants. How to handle email signatures after a merger, from day one to the tenant move.
What are Outlook roaming signatures, and should you turn them off? Roaming signatures store a person's Outlook signatures in their Exchange Online mailbox rather than on one computer, so a signature made in one Outlook appears in the others. That is convenient for a person managing their own signature. For an organisation that sets signatures centrally, it is one more place an old or personal signature can come back from, and many administrators choose to turn it off.
For most of Outlook's life, a signature was a file on a computer. Make one on your desktop and your laptop knew nothing about it. Outlook on the web had its own signature setting, stored separately.
Roaming signatures moved the signature into the mailbox. A signature created in Outlook on the web, the new Outlook for Windows or a current version of classic Outlook is stored with the mailbox and offered in the others. People like it, because they set it once.
Three things change when signatures roam:
Exchange Online has an organisation setting for this, PostponeRoamingSignaturesUntilLater, set with the Set-OrganizationConfig cmdlet in Exchange Online PowerShell. It covers Outlook on the web and the new Outlook for Windows. Classic Outlook for Windows is controlled separately on each device, through the device management your organisation already uses.
Turning roaming off stops signatures being stored and synced with the mailbox. It does not on its own stop people adding a signature in Outlook, because the signature option itself is a separate setting, held in the Outlook on the web mailbox policy.
It depends on who owns the signature:
| If signatures are... | Then... |
|---|---|
| Written by each person, with no central tool | Leave roaming on. It saves everyone setting the same signature up three times. |
| Added centrally, and you want one consistent signature | Turn roaming off, and turn off the signature option, so Outlook inserts nothing of its own. |
| Added centrally, but people may keep a personal sign-off | Leave them on, and accept that some messages will carry both. |
Both of the last two are reasonable. The point is to choose, rather than find out from a customer that your emails carry two signatures.
Footer365 asks the question once, in the setup wizard, at the stage Everyone's own Outlook signatures, and again on the Getting started page if you want to revisit it:
Two things to know before choosing the second. Turning people's own signatures off clears the signatures they have already saved, and that wording does not come back if the feature is switched on again later. And classic Outlook for Windows keeps its own signatures either way, because that is a device policy rather than something Footer365 can change. Our guide to keeping or turning off people's own Outlook signatures covers both in full.
Work through the causes in order: personal Outlook signatures first, then any older disclaimer rule still running in Exchange, then a second signature product still connected. Our troubleshooting article on signatures that appear twice or stack up walks through each one, with where to look in the Exchange admin center.
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Two companies, two brands and often two Microsoft 365 tenants. How to handle email signatures after a merger, from day one to the tenant move.
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