Deleting an old Outlook signature only works if you delete it in the right store. A cleanup guide for Windows, web, Mac, and mobile Outlook.
The MailSigCraft Team
MailSigCraft
You changed jobs, rebranded, or just got tired of an old title on every email — so you opened Outlook's signature settings, deleted the text, and moved on. Then it showed up again: on your phone, on a coworker's screen, in a reply you didn't touch. Outlook doesn't have one signature to delete. It has up to four, stored in places that don't talk to each other, and clearing the text in one leaves the other three untouched.
"Outlook" covers five different interfaces built on four separate storage systems: New Outlook for Windows and Outlook on the web share one cloud store, classic Outlook for Windows keeps a local file, Outlook for Mac has its own independent store, and Outlook mobile is local to the device. The menu path to delete a signature is different in each one, so the first step is identifying which you're in — the picker below does that from a screen description.
In every version, clearing the text inside the signature editor box only edits that signature — it doesn't remove the entry. You need to select the signature by name in the list and click the trash/delete/minus control next to it. An edited-to-blank signature can still get auto-inserted by name if a dropdown still points at it.
Outlook keeps two separate slots: one for new messages, one for replies and forwards. Deleting a signature that was assigned to either slot resets that slot to "(none)" — it does not automatically fall back to a different signature, and it does not clear itself from a slot you forgot to check. This is the single most common reason a "deleted" signature still appears in some messages but not others.
A compose window or mobile draft that was open before you deleted the signature keeps the old copy loaded in memory for that session. Close the draft (or force-quit the mobile app) and start a fresh message to confirm the change actually took.
How to tell: Rounded top toolbar, a left-hand app rail, and “Try the new Outlook” already toggled on.
Based on Microsoft's published menu paths for each Outlook 365 surface as of mid-2026. Not a live check of your tenant — a reliability read on which store you're clearing.
Every Outlook version treats a signature as a named object with a preview box beneath it — the name in the list and the HTML content are two different things. Selecting the text inside the box and hitting backspace edits the content but leaves the named entry (and any dropdown pointing at it) in place. The delete/trash control next to the name in the list is a separate action, and it's the one that actually removes the signature.
Always delete from the list by name. If you only ever see a text box and never a list with delete controls, you're mid-edit on the wrong control — scroll up to the signature list itself.
Outlook lets you assign a different signature — or none — to new messages versus replies and forwards. Most people only look at the top dropdown, fix it, and close the settings panel without scrolling to the second one. If the old signature was only ever assigned to replies (a common setup for a shorter reply-specific block), deleting the "main" one leaves the reply version live and confusing.
Open the signature settings again after any delete and confirm both dropdowns — not just the one you remember setting.
New Outlook for Windows and Outlook on the web share one cloud-based signature list — delete there and both clear. Classic Outlook for Windows keeps its own file on that one PC. Outlook for Mac and Outlook mobile each keep a fourth and fifth independent copy. None of these four stores read from each other automatically. If you deleted the signature in classic Outlook on your work laptop, it's still sitting untouched in the cloud store, on your Mac, and on your phone.
Repeat the delete on every surface you actually use — the picker above has the exact steps for each one.
Outlook loads the assigned signature into a new message or reply at the moment you open it, then holds that copy for the life of the draft. Deleting the signature in Settings while an old draft is still open doesn't retroactively strip it from that draft, and depending on the client, a stale New Outlook or web tab can also hold the pre-delete signature list until it's refreshed.
Close every open compose window and draft before judging whether the delete worked, and refresh the browser tab if you're on Outlook on the web.
A block that reappears identically for everyone on your domain — a legal disclaimer, a company banner, a "sent from our support team" line — is usually injected centrally by an Exchange mail flow rule (a "transport rule"), not by anything stored in your personal Signatures settings. End users can't remove a transport-rule disclaimer from the Signatures menu because it was never added there; it gets appended to the message after you hit send, on the server side.
If the block survives every delete on every device, ask your Microsoft 365 admin whether a mail flow rule is adding it — that's the only place it can be turned off.
Both read the same cloud-stored signature list, so removing it in either one removes it in the other. The easiest pair to clean up.
Stored on that machine only. If you use classic Outlook on more than one PC, you're repeating the delete on each one separately.
Not connected to the Windows or web stores at all — a Mac signature has to be deleted on the Mac, full stop.
Local to the app install. Deleting it on one phone doesn't touch a tablet or a second phone signed into the same account.
Only if those devices read from the same store. New Outlook for Windows and Outlook on the web share one cloud store, so a delete on either clears both. Classic Outlook for Windows, Outlook for Mac, and Outlook mobile each keep their own separate copy and have to be cleaned up individually.
Almost always one of two things: a default dropdown (new messages or replies/forwards) still points at the deleted signature's name, or you deleted it in one store while another device is reading from a different, untouched store. Work through the checklist above in order.
Open the shared mailbox in Outlook (or add it as an additional account) and go through the same Signatures settings while that mailbox is the active context — a shared mailbox's signature is stored separately from your personal one, even though you're using the same app window.
Not from the Signatures menu — a disclaimer that appears identically for every sender on the domain is usually added by an Exchange mail flow rule on the server side, after you hit send. Only a Microsoft 365 admin can edit or remove that rule.
Check whether the default dropdown reset to a different leftover signature rather than "(none)." Some clients auto-select the next signature alphabetically if the assigned one is deleted rather than leaving the slot blank.
Yes, for images pasted or embedded directly in the signature — they're stored as part of that signature entry and go with it. An image referenced by an external URL (rather than embedded) simply stops being called; nothing external gets deleted.
An old Outlook signature rarely survives because of a glitch — it survives because "delete" only ever touches one of up to four separate stores, and because the new-message and reply/forward defaults are two different settings that both need checking. Delete by name (not by clearing text), check both default dropdowns, and repeat the process on every Outlook surface you actually use before assuming it's still broken.
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