How to fix Outlook error 0x80040610

Plain English

What error 0x80040610 actually means

When Outlook throws 0x80040610 during a send/receive, it's telling you that a message it's trying to move is either too big for the server or the item itself has gone corrupt. Because Outlook processes the Outbox in order, that one bad message sits at the front of the queue and jams everything behind it — so nothing sends and, on some accounts, nothing receives either.

You'll often see this phrased two ways: "the message being sent exceeds the message size established for this user" (an oversized attachment) or a generic "reported error (0x80040610): sending/receiving reported error" (a corrupt item or a damaged Outlook data file, the .pst). The good news: both come down to the same short list of fixes, and none of them are risky if you follow the steps in order.

This affects classic Outlook on Windows — Outlook 2016, 2019, 2021 and the desktop app in Microsoft 365. We support Windows and the Outlook Android app; we don't cover Apple Mail or Mac Outlook.

If it keeps returning

Repair the data file with scanpst.exe, then compact it

A persistent 0x80040610 with nothing in the Outbox usually means your .pst (or .ost) data file has minor corruption. Microsoft ships a free repair tool for exactly this — the Inbox Repair Tool, scanpst.exe. Close Outlook completely before you start.

1. Find SCANPST.EXE. On 64-bit installs of Outlook 2016, 2019, 2021 or Microsoft 365 it lives at C:\Program Files\Microsoft Office\root\Office16; on 32-bit Outlook it's under C:\Program Files (x86)\Microsoft Office\root\Office16 instead. Double-click it.
2. Click Browse and point it at your data file. Personal .pst files are usually in C:\Users\<you>\Documents\Outlook Files.
3. Click Start. It scans and reports any inconsistencies. If it finds errors, tick Make a backup of scanned file before repairing, then click Repair. Run it two or three times until it comes back clean.
4. Reopen Outlook and test with F9.

Finally, compact the file so it shrinks and tidies itself: File > Account Settings > Account Settings > Data Files, select your PST, click Settings > Compact Now. A slimmer, defragmented file is far less likely to jam again.

One safety note: for a POP3 account your PST is the only copy of that mail, so let scanpst make its backup first. For IMAP, Microsoft 365 or Outlook.com accounts the mail lives on the server and re-downloads, so there's nothing to lose.