November 2, 2025
Thumbs-up vs thumbs-off
Stop Microsoft users sending 'reactions' to email by adding a postfix header
Inbox war over email “likes”: make it stop vs just chill
TLDR: A sender blocks Outlook “likes” by adding a “no reactions” header, causing clients to gray out or silently drop them. Commenters split between anti-sticker purists and convenience fans, with jokes about auto-replies and warnings that standards may bring reactions to every inbox.
A fed‑up sender found a secret switch to stop Microsoft’s cutesy email “reactions” — by adding a special header that tells Outlook, “no thumbs-ups, thanks.” It’s the digital equivalent of taping a “do not disturb” sign to every message. The move worked: some Outlooks greyed out reactions, others tried to send a “like” and got ghosted by Microsoft’s servers. Cue drama. mouse_ snarked, “It seems your colleagues do,” suggesting the office wants quick taps, not essays. infogulch shrugged: “Is it really that annoying?” Meanwhile ifh-hn pitched pure chaos: auto-reply with, “reaction not received, send a real email cheers.” The crowd cackled.
Old‑school email fans cheered the header hack as a boundary — no sticker spam in their inbox. Reaction enjoyers call it grumpy gatekeeping. The plot thickens with Avamander warning this isn’t just a Microsoft thing — standards like RFC 9078 mean reactions could spread across more mail apps. And yes, this fight has history: a previous thread exploded with hundreds of comments.
Bottom line: a simple header sparks a culture war — email as conversation vs email as confirmation. One side wants readable messages; the other wants low-friction “got it” taps. Everyone agrees on one thing: silent drops are a terrible user experience, even if they do keep the inbox quiet.
Key Points
- •Microsoft supports an email header (x-ms-reactions: disallow) to disable reactions on messages.
- •The article implements the header server-wide using Postfix header_checks with PCRE and a PREPEND rule.
- •Final placement used inserts the x-ms-reactions header before the Date header and is verified in sent messages.
- •Behavior varies across Outlook clients: some still show reactions but server-side blocks; others gray out the option.
- •Microsoft indicates the disallow feature is rolling out at different cadences, with server-side enforcement as backup.