Stop iCloud From Wiping Your Apple Mail Signatures (Permanent Fix)
If your signatures vanish repeatedly — not just once after an update — you almost certainly have an iCloud sync conflict: one of your Macs keeps overwriting the shared signature set. Here's how the sync works and how to end the war.
Step by step
Understand what's actually syncing
With iCloud Drive's Mail toggle on, your signatures live in a shared iCloud container (~/Library/Mobile Documents/com~apple~mail/…) that every Mac on your Apple ID reads AND writes. Any Mac with a stale copy can push it over your fresh one. (iPhones aren't involved — this container is Mac-only.)
Inventory every Mac on the account
The clobbering culprit is usually a forgotten one: the old MacBook in a drawer, the work iMac, a machine restored from an old backup. Every Mac signed into your Apple ID with Mail configured is a suspect.
Make the iCloud setting consistent everywhere
On EVERY Mac: System Settings → your name → iCloud → iCloud Drive → Apps syncing to iCloud Drive → Mail. All on, or all off — a mixed fleet is exactly what causes flip-flopping signatures.
Let one Mac win
On your primary Mac, with all others asleep or Mail quit, rebuild/verify your signatures. Then open Mail on the others and confirm they RECEIVED the set rather than pushing their own.
If it still flaps, isolate the writer
Quit Mail on all Macs. Fix signatures on the primary. Open the other Macs one at a time, checking after each — the one whose launch wipes your set is the machine with the corrupt local state. On that Mac, quit Mail, delete its stale Signatures folder contents (see the recovery guide for paths), and reopen.
Keep a re-installable copy
Whatever the sync does next, you want the signature to be one click away — keep the HTML somewhere safe, or in Autograph's library, where reinstalling takes seconds instead of an afternoon.
Signatures that survive the sync wars
Autograph keeps every signature in its own library, outside the conflict zone — whatever iCloud does, reinstalling into Apple Mail is one click.
Download Autograph free See the templatesCommon questions
Does turning off iCloud Drive for Mail delete my signatures?
No — it disconnects that Mac from the shared set and falls back to local signatures (~/Library/Mail/V…/MailData/Signatures). You may need to recreate them locally, but nothing in iCloud is deleted.
Why do edits made on one Mac revert an hour later?
Another Mac pushed its older copy. That's the conflict this guide fixes — find the writer (step 5).
Is my iPhone part of this sync?
No. iPhone signatures are a separate on-device setting — see the iPhone guide. This container syncs Macs only.