Outlook is slow, freezes or will not open: safe mode, add-ins and a new profile

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The short answer: a slow Outlook, one that freezes (“Not Responding”) or will not open at all, almost always has its cause on the computer rather than in the mailbox: a misbehaving add-in, a large or damaged data file, or a broken profile. Safe mode tells you straight away which side the problem is on.

Symptoms and causes

Symptom Most likely cause
Stuck on “Loading profile” or “Processing” An add-in or the data file. Open in safe mode to tell the two apart.
Opens, but freezes on every message An add-in (antivirus, PDF writer, CRM, signatures) scanning each e-mail.
Slow only in one huge folder Many thousands of messages in a single folder. Archive or split it.
Closes by itself when opening A damaged profile or data file, or an Office update half done.
Slow after a Windows or Office update An Office repair usually fixes it.

Making Outlook fast again

1 Open in safe mode: press Windows+R, type outlook.exe /safe and Enter. If it is fast that way, an add-in is to blame.
2 Switch the add-ins off: in File > Options > Add-ins, at the bottom choose COM Add-ins > Go and untick them all. Turn them back on one at a time until you find the slow one.
3 Repair the data file if safe mode is slow too: repairing the Outlook data file.
4 Create a new profile: in Control Panel, open Mail > Show Profiles > Add, set the account up (with IMAP the mail comes back from the server) and choose “Always use this profile”. Keep the old one until you have checked everything.
5 Repair Office: in Windows Settings, under Apps, choose Microsoft Office, Modify > Quick Repair.
6 Lighten the mailbox: folders with years of attachments make everything heavier, in Outlook and on the server: your mailbox is full.
A new profile with a POP account does not bring the mail back. With POP the history is in the old profile’s PST file: open that PST in the new profile (File > Open > Open Outlook Data File) instead of losing it.
If webmail is slow too, the problem may be the mailbox or the server rather than the computer: then tell us.

Outlook still slow or will not open? Tell us the Outlook version and what appears on screen.

Open a support ticket

SEE ALSO

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

Outlook search does not find e-mails: rebuilding the index

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

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

How to set up your e-mail in the new Outlook for Windows

Webmail or an e-mail app: which one to read your mail with

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