Why Am I Getting Duplicate Emails?
Seeing the exact same email land twice — or three, four times — feels like it should mean something's seriously wrong, but the actual causes are almost always mundane and fixable.
1. The account is set up more than once on the same device
The single most common cause. If you've added the same account twice in a mail app — maybe once manually and once through an auto-detected setup you forgot about — you'll get every message doubled. Check your accounts list for the same address appearing more than once.
2. A mail app's local sync got confused
Desktop and mobile mail apps keep a local copy of your mail and periodically reconcile it with the server. Occasionally that reconciliation goes wrong, and the app re-downloads messages it already has instead of recognizing them as already present. This tends to clear up with a fresh sync — remove and re-add the account, or in apps like Apple Mail, rebuild the mailbox.
3. A forwarding loop
If two accounts are both set to forward to each other, even indirectly through a chain of rules, a single message can bounce back and forth and generate duplicates each time. Check your Forwarding and Filters settings for anything that might be sending mail somewhere that eventually routes back to the same inbox.
4. The sender genuinely sent it twice
Sometimes it's just this simple — an automated system retried a send after a slow or failed first attempt, and both actually went through. This is common with newsletters, receipts, and other automated mail. Nothing to fix on your end in this case.
5. A filter rule is copying instead of moving
If you've set up a rule to file certain mail into a folder, double-check it's actually configured to move the message, not copy it. A misconfigured "copy" rule leaves the original in the inbox and adds a duplicate in the target folder — which can look like a duplicate email when it's really the same rule doing exactly what it was told, just not what you meant.
What to actually do
- Check your accounts list for the same address set up twice.
- Check filters and forwarding rules for anything that could be looping mail back to itself.
- If it's isolated to one app, remove and re-add the account to force a clean resync.
- If it's genuinely coming from the sender's side (a newsletter, a receipt), there's usually nothing to fix — it's on their end, not yours.