Outlook is not syncing: missing e-mails and folders that do not update

E-mail·· 6 views· 4 min read

The short answer: when Outlook stops showing new mail, or a folder freezes in time, it is nearly always one of four things: Outlook is offline, the account is POP rather than IMAP, the folder is not subscribed, or Outlook’s data file (the OST) is corrupted. First, the webmail test: open webmail with the same account. If everything is right there, the server is fine and the problem is in Outlook or the computer. If webmail fails too, the problem is on the server side and we fix it.

Symptoms and causes

Symptom Most likely cause
Nothing new arrives, and there is no error Outlook is in Work Offline mode, or the account dropped out of the Send/Receive group. See Outlook shows Disconnected or Working Offline.
A folder exists in webmail but not in Outlook The folder is not subscribed in Outlook. With IMAP, Outlook only shows subscribed folders.
What I delete on the phone comes back on the computer (or the other way round) One of the accounts is POP. With POP each device keeps its own copy and they do not talk: POP or IMAP.
Error 0x8004010F or “the data file cannot be accessed” Outlook cannot find or open its data file (OST/PST). It can be repaired or rebuilt: repairing the Outlook data file.
Error 0x800CCC0F or “the connection was interrupted” The connection dropped halfway: an unstable network, an antivirus scanning e-mail, or a very large message being downloaded.
Only recent e-mails sync Outlook is set to keep only a period offline (for example, the last year). The older ones are still on the server.

Getting sync moving again

1 Make sure you are online: on the Send/Receive tab, the Work Offline button should not be highlighted. Then press Send/Receive All Folders (or F9).
2 Make sure the account is IMAP: in File > Account Settings, the type column should say IMAP. If it says POP, follow POP or IMAP to switch without losing mail.
3 Subscribe the missing folders: right-click the account name, choose IMAP Folders, press Query, select the folders and Subscribe.
4 Check how much stays offline: in File > Account Settings > Change, the “Mail to keep offline” slider decides how many months stay on the computer. Move it to All if you need the whole history.
5 If a single folder stays frozen, right-click it, Properties > Clear Offline Items, and let Outlook download it again from the server. What is on the server is not lost.
6 If none of this works, the OST file may be damaged: close Outlook and rebuild it as explained in repairing the Outlook data file.
Do not delete the account to “start over” without knowing whether it is POP or IMAP. With IMAP the mail is on the server and downloads again. With POP it may exist only on that computer, and deleting the account deletes it. If in doubt, take a copy first or ask us.
A full mailbox also stops sync. If the server refuses messages for lack of space, nothing new reaches any device: your mailbox is full.

Tried everything and Outlook still will not sync? Tell us the account address and what you see in webmail.

Open a support ticket

SEE ALSO

Outlook shows Disconnected or Working Offline: how to get it back online

Repairing the Outlook data file: damaged PST or OST, SCANPST and a new OST

POP or IMAP: which to choose, and what you lose by picking wrong

Common Outlook errors: 0x800CCC0E, password prompts and more

Your mailbox is full: what to delete and how to stop it happening

How to access your webmail

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