Thunderbird Not Receiving New Mail
Worth being clear up front: this is different from a connection error. Thunderbird shows as connected, nothing's throwing an error — new mail just isn't showing up. Getting an actual connection error instead? That's our guide on Thunderbird won't connect to server.
1. Check the fetch interval
- Account Settings → Server Settings → confirm "Check for new messages every X minutes" is set to something reasonable, not disabled.
- Manually trigger a check — File → Get New Messages for All Accounts — to rule out a timing issue before digging further.
2. Check folder subscriptions
If new mail's arriving in a folder Thunderbird isn't subscribed to, it simply won't show up. I see this a lot on IMAP accounts with folders created outside Thunderbird itself.
- Right-click the account name → Subscribe.
- Make sure Inbox and everything else you use is checked.
3. Check for a filter silently moving mail
- Tools → Message Filters — look for anything routing incoming mail somewhere other than the Inbox before you'd ever see it.
- Also check Junk — Thunderbird's built-in detection can be more aggressive than people expect.
4. Global Inbox vs. per-account view
If you use the Unified/Global Inbox view, new mail can sometimes only show in the per-account folder rather than the unified one, or the reverse, after a settings change. Check both before concluding nothing's arriving at all.
5. Corrupted local folder index
Thunderbird keeps a local index per folder, and it can quietly drift out of sync with what's actually on the server.
- Right-click the affected folder → Properties → Repair Folder.
- This rebuilds the local index without touching anything server-side.