The fix for Outlook signatures that appear on new emails but disappear from replies and forwards — with the five separate causes (New vs Classic Outlook, per-account dropdown, roaming signature overrides, plain-text reply mode, and mobile Outlook stripping).
The MailSigCraft Team
MailSigCraft
The confusing part isn't that your Outlook signature is missing — it's that it's inconsistent. New emails carry the signature fine. Replies show up blank, or with the wrong signature, or with the signature from a mailbox you don't even use anymore. The root cause is that Outlook treats "new messages" and "replies/forwards" as two completely separate signature slots, and each one is set independently per account, per Outlook variant, and per device. There are five distinct places this can quietly break.
This guide covers the 30-second fix, plus the four other traps that catch you when the dropdown fix doesn't stick — the New Outlook vs Classic branching behavior, roaming-signature overrides on Exchange, plain-text reply mode, and the mobile Outlook signature-stripping quirk.
If the signature works on new emails and not replies, it's almost always the second dropdown. Here's the four-tap fix in Outlook desktop:
Classic Outlook: File → Options → Mail → Signatures… button. New Outlook / Outlook on the web: Settings gear → Mail → Compose and reply.
In the top-right of the Signatures panel, there are two dropdowns labelled New messages and Replies/forwards. Each is independent. The one you care about right now is the second one.
By default, this is set to (none). Change it to the signature you want on replies — usually the same signature as new messages. If you keep a shorter reply-specific signature, set that one instead.
The dropdowns are set per account — the account selector is above them. If you have Gmail + work + iCloud accounts in one Outlook profile, each has its own dropdowns. Change them all, or the account that's still broken will silently keep sending replies with no signature.
Compose a reply to any email in your inbox. The signature should appear immediately. Testing with a new email won't reveal the fix worked — that case was already working.
If you set the dropdown and replies still ship without the signature, one of these is happening.
If you've been switched to New Outlook (Microsoft's rewrite that replaced Classic Outlook for most Windows users through 2024–2025), your signatures don't migrate over automatically from Classic. The Signatures editor in New Outlook reads from a cloud-stored "roaming signature" that lives in your Exchange mailbox — not from the local .htm files Classic Outlook used. If you set up your signature in Classic and later switched to New, replies from New Outlook can silently use (none) because the roaming signature is empty.
The fix: in New Outlook, open Settings → Mail → Compose and reply, and re-create the signature from scratch (or paste it in from a desktop editor). Don't try to import from Classic — the file paths are different and the migration has been unreliable through mid-2026. Setting it fresh in New Outlook writes it to the roaming location so replies pick it up.
For work accounts on Microsoft 365 / Exchange Online, Microsoft rolled out cloud-stored roaming signatures in 2022. The idea was that your signature would sync across Outlook desktop, Outlook web, and Outlook mobile automatically. In practice, the roaming signature and the local signature can drift — if you edit the local one, Outlook might quietly overwrite it with the (older) roaming version the next time it syncs, and replies use the roaming one while new emails somehow use the local one.
The fix: decide which one is your source of truth. If you want the roaming (cloud) signature, edit it in Outlook on the web — the change syncs to desktop and mobile. If you want the local signature, disable roaming for that account (Group Policy for enterprise, or HKCU\Software\Microsoft\Office\16.0\Outlook\Setup\DisableRoamingSignaturesTemporaryToggle = 1 for personal use). Editing both locations independently is what causes the reply-vs-new inconsistency.
Outlook has a plain-text reply setting that some organizations enable by default for compliance, and some users toggle on accidentally. When a reply is composed in plain-text mode, HTML signatures get stripped — no logo, no formatting, sometimes no text at all if the signature was image-only. The new-email case works because new messages default to HTML unless explicitly changed.
The fix: File → Options → Mail → Compose messages — set the format to HTML (not plain text). Separately, check Replies and forwards in the same panel: some Outlook builds have a "Preserve original message format" option that can force plain-text replies when the sender's original message was plain text. Disable it if replies are stripping formatting.
Outlook mobile (iOS and Android) has a well-known behavior where the signature configured in mobile settings applies to new emails but gets stripped or shortened on replies — especially replies to threads with quoted history. This isn't a bug you can fix; it's how mobile Outlook is built. Recipients see the signature on your first message but not on your reply-all in the thread.
The fix: for mobile-heavy senders, keep the mobile signature identical to desktop and short (3–4 lines max), so even if it gets partially stripped, the identity block survives. Do NOT try to make it a long HTML block on mobile — Outlook mobile's HTML support in the signature field is limited, and the signature you type in mobile settings should be plain text with a link or two.
Outlook has five variants in the wild through 2026 and the path is different in each. If a tutorial you're following doesn't match your Outlook, that's why the fix isn't working.
The legacy desktop app. Reads signatures from local .htm files at %APPDATA%\Microsoft\Signatures\. Both dropdowns live in the Signatures dialog, top-right.
The rewrite that replaced Classic on most Windows machines. Reads from Exchange roaming signature. No local .htm files — everything is cloud.
Same UI as New Outlook — they share the same codebase. Roaming signature only. Edit here and desktop/mobile pick it up.
Uses a hybrid model — local signature file plus roaming sync if enabled. New-vs-reply dropdown is in the account settings panel, not the Signatures editor itself. Common trap.
If you use Outlook across Windows desktop, Mac, web, and mobile, don't manage five signatures. Build one HTML signature once, save it as a paste-source, and paste it into each variant's Signatures editor. MailSigCraft generates the HTML plus a plain-text fallback from one input so the version on your web Outlook matches the version on your Mac and your phone.
The diagnostic shortcut: match the symptom to the trap.
Every reply in a long email thread carries your full signature stacked underneath the previous ones. If your signature is the full block — logo, headshot, title, phone, LinkedIn, address, disclaimer — a 20-reply thread becomes visually bloated.
Jane Smith
Senior Designer, Acme Corp
[large logo image]
+1 555 123 4567
jane@acme.com · linkedin.com/in/janesmith
123 Market St, San Francisco, CA
Confidentiality Notice: This email contains…
Repeats in full at the bottom of every reply. In a 15-message thread, the signature block outweighs the actual conversation.
Jane Smith
Senior Designer, Acme — acme.com
Three lines. Identifies who you are, gives one place to find you, doesn't stack awkwardly in threads. The full signature already went with your first email in the conversation — replies don't need it again.
This is where Outlook's separate New-vs-Reply dropdowns are actually useful, not just a source of confusion. Set the New messages dropdown to your full signature (recipients see it on first contact) and set the Replies/forwards dropdown to a short 2-3 line version. In the Signatures editor, create two signatures — "Full" and "Reply" — and set the dropdowns accordingly.
Before you close the ticket:
Reply to any email in your inbox. The signature should appear immediately in the compose window, not just after send.
Reply-all to a thread with 3+ messages. Confirm the signature appears exactly once, at the bottom of your new reply — not stacked with the sender's original.
Forward an email. Forwards use the same "Replies/forwards" dropdown — if replies work but forwards don't, one dropdown got missed.
If you use multiple accounts, send a test reply from each one. The dropdown is per-account; every mailbox needs its own configuration.
The root of this whole class of problems is that Outlook was designed around the assumption that most people want a different signature on replies — shorter, less branded, more conversational. That assumption was probably right in 2003. In 2026, most professionals want the same signature everywhere for brand consistency, and the two-dropdown UI keeps producing surprised users who set one and think they're done.
The other half of the pain is that Microsoft is mid-migration from Classic to New Outlook, and the two products handle signatures differently (local files vs. roaming), so guidance from even two-year-old blog posts might be pointing at the wrong menus. If the fix in this guide didn't work, the first thing to check is which Outlook you're actually running — Help → About Outlook shows the version — and whether the tutorial matches.
The reason "which Outlook are you using?" is such a common support question is that most people manage 3–5 different signature configurations (Classic Outlook, New Outlook, web, Mac, mobile) and none of them auto-sync reliably. MailSigCraft generates one canonical HTML signature and a plain-text fallback from a single input, so the version you paste into New Outlook is bit-identical to what you paste into Outlook on the web and Outlook for Mac. When roaming signatures sync (or don't), you have a source of truth to re-paste from.
Check mobile Outlook separately. Mobile has its own signature setting under Settings → Signature, entirely independent of desktop.