Overview
If your Gmail signature looks broken — missing logos, lost fonts, odd spacing, stripped-out links — only when your Vacation Responder (Out of Office) is turned on, you've hit one of Gmail's most common formatting conflicts.
Gmail treats the auto-reply and the signature as a single block of content. If either side is set to Plain Text, Gmail strips the formatting from the other to keep them consistent. The result is a signature that displays perfectly in normal replies but falls apart the moment your OOO is active.
This article walks through every fix and edge case in the order you should check them.
Before You Start
Two minutes of preparation will save you a lot of trial and error.
Back up your existing signature. Open Settings → General → Signature, click into the signature box, press Ctrl+A then Ctrl+C, and paste the contents into a Google Doc or a plain text file. If a fix breaks something further, you have a clean copy to restore.
Set up a test method. Gmail will not send a vacation reply to yourself, so you cannot test the fix from the same account. Use one of the following:
A non-Gmail address you control (Outlook, Yahoo, iCloud, or a work account on a different domain).
A second Google account, sent through a different browser or incognito window.
The "Send mail as" feature from another verified account.
Note the 4-day rule. The Vacation Responder will only auto-reply to the same sender once every four days. To re-test from the same email address, you'll need to wait, use a different sender, or temporarily disable and re-enable the responder (which resets the tracking).
Fix 1: Enable Rich Text in the Vacation Responder
When the auto-reply is in Plain Text mode, Gmail forces your signature into plain text to match — which is what breaks images, hyperlinks, and styling.
Open Gmail and click the gear icon in the top-right corner.
Select See all settings.
Stay on the General tab and scroll to Vacation responder.
Look at the toolbar above the message body:
If you see a "Rich formatting" link, click it to switch out of Plain Text mode.
If formatting controls (Bold, Italic, font selector) are already visible, you are already in Rich Text mode — move to the next step.
Refresh the link. Even if the message looks correct, delete one character and retype it. This forces Gmail to re-link the auto-reply with your signature.
Scroll to the bottom and click Save Changes.
Send a test email from your test account. The signature should now render correctly in the auto-reply.
Fix 2: Confirm You Edited the Right Signature
Since 2020, Gmail supports multiple signatures with separate defaults for new emails and for replies/forwards. The Vacation Responder uses the "On reply/forward" default — not the new-email default.
This catches a lot of users: they update the wrong signature, don't see a change in their auto-reply, and assume the fix didn't work.
Go to Settings → General → Signature defaults.
Look at the two dropdowns:
For new emails use
On reply/forward use
Make sure the signature you edited is the one selected under On reply/forward.
If they're set to different signatures, decide whether to (a) edit the reply signature to match, or (b) change the dropdown to use the same signature for both.
Click Save Changes.
Pro Tip: Need more advanced control over your inbox signatures? You can easily manage reply and forward signatures directly from your browser using the BulkSignature Chrome extension.
Fix 3: Anchor the Signature Above Quoted Text
By default, Gmail places signatures at the very bottom of long reply threads, sometimes hidden behind the "…" (trimmed content) marker. When the Vacation Responder is active, this can push your signature into the trimmed zone, where recipients never see it.
Go to Settings → See all settings → General.
Scroll to the Signature section.
Check the box labelled:
Insert signature before quoted text in replies and remove the "--" line that precedes it.
Click Save Changes at the bottom of the page.
Your signature will now stay attached to the active message rather than disappearing into the bottom of long email chains.
Fix 4: Turn Off Plain Text Mode in the Compose Window
The compose window has its own Plain Text toggle, separate from the Vacation Responder setting. The keyboard shortcut to toggle it is Ctrl+Shift+P (or ⌘+Shift+P on Mac), which users hit by accident more often than you'd expect — and once it's on, every email you send strips out signature formatting until you turn it off again.
Click Compose to open a new message.
In the bottom-right corner of the compose window, click the three vertical dots (More options).
If Plain text mode has a checkmark beside it, click to uncheck it.
Close and reopen the compose window. Your signature should reload with full formatting.
Fix 5: The "Ghost Signature" Workaround
If the signature still breaks only when the auto-reply is active, you can bypass Gmail's automatic merging entirely.
Open Settings → General → Signature and copy the full content of your signature block.
Scroll down to Vacation responder and paste the signature directly into the bottom of the auto-reply message body.
Temporarily switch your default signature to No signature while you're away.
Save changes.
This gives you complete control over the layout during your leave. When you return, switch your default signature back on and clear the pasted version from the Vacation Responder.
Edge Cases
Mobile (iOS and Android)
Gmail's mobile apps maintain completely separate signature settings that do not sync with the web version. If you only use the mobile app to send mail, fixing the web signature won't change anything.
To update the mobile signature:
Open the Gmail app and tap the menu icon (top-left).
Scroll to Settings, then tap your account.
Tap Mobile signature (iOS) or Signature settings (Android) and edit the text.
Mobile signatures are plain text only on iOS and limited HTML on Android. If you need a fully formatted signature on mobile, send mail through the web interface or use a third-party signature manager.
"Send mail as" and Aliases
If you send mail through Gmail using a custom address (for example, a domain alias or external SMTP), each alias has its own signature setting. The Vacation Responder uses the signature attached to the address it's replying from.
Go to Settings → Accounts and Import.
Confirm which alias is set as the default sender.
Update the signature for that specific alias under Settings → General → Signature (use the dropdown above the signature editor to switch between addresses).
Workspace Admin Overrides
If you're on a Google Workspace (business) account and none of the fixes above are working, your administrator may be enforcing a global signature template through the Admin Console (Apps → Google Workspace → Gmail → Compliance → Append footer). This silently overrides personal signatures and can conflict with the Vacation Responder.
You won't be able to fix this yourself — contact your IT administrator and reference the Append footer compliance setting.
Inline Images and Logos
Even with Rich Text enabled, image-heavy signatures can still render badly. Common causes:
Images hosted behind authentication (corporate intranets, private Drive folders) won't load for external recipients.
Hotlinked images larger than Gmail's rendering limit are stripped or replaced with a "View image" link.
Transparent PNG logos disappear against dark-mode backgrounds in many clients.
Outlook blocks external images by default — recipients see a placeholder until they click "Download images."
For business signatures, host logos on a public CDN, use light-friendly versions of dark logos (and vice versa), and keep image dimensions under 600px wide.
Recipient-Side Rendering
A signature that looks perfect in Gmail can still break for the recipient. Outlook uses Word's HTML rendering engine, which strips a wide range of CSS. Apple Mail handles HTML well but can mis-render web fonts. Plain-text mail clients ignore HTML entirely.
"Fixed" in this article means "Gmail is sending the signature correctly." How it displays on the other end depends on the recipient's client, and is outside Gmail's control.
When the Auto-Reply Isn't Sending at All
If the issue isn't formatting but that recipients aren't getting the auto-reply at all, check the audience filters at the bottom of the Vacation Responder settings:
"Only send a response to people in my Contacts" — limits replies to addresses already in your Google Contacts.
"Only send a response to people in [your domain]" — Workspace-only; limits replies to internal colleagues.
If either is checked, external senders won't receive a reply regardless of how the signature is configured.
Why This Happens
Gmail's Vacation Responder is one of the older features in the product, and it predates the current Signature editor. When both are active, Gmail merges them into a single outgoing message. If the Vacation Responder isn't set to Rich Text, Gmail interprets that as a request for a plain, unstyled email and removes the HTML from your signature to match.
Enabling Rich Text on the auto-reply tells Gmail it's safe to keep the formatting intact.