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Outlook for Mac Not Syncing – How to Fix It 2026 Guide

Why Choose Keith Thomas

20 years of experience as a Senior Apple Support Specialist at Apple Computer UK HQ.

• Former Apple Computer UK Mac Support Specialist and Apple Authorised Service Provider background.

Established and Independent since 2010 for on‑site Apple Support Service – no call centres, no outsourcing, no hardware repairs. Over 25,000+ Apple problems resolved. Unique on-site Apple Support Service. backed up with Independent Apple Telephone Support Assistance.

• Trusted by home users, small businesses, and professionals across London and the South East UK.• Clear, honest, software‑only support. No Hardware Repairs. Expert Apple Consultancy Service.

On‑site Apple Mac Support in London and the South East UK

What this page covers

This guide explains the real reasons Outlook for Mac stops syncing, the steps you can try yourself, and when it’s time to get professional on‑site help. It applies to:

• Outlook for Microsoft 365

• Outlook.com accounts

• Exchange and Office 365 business accounts

• Gmail, iCloud and IMAP accounts added to Outlook

If Outlook for Mac won’t send or receive emails, shows “Not Connected”, syncs slowly, or only updates sometimes, this page is for you.

The most common reasons Outlook for Mac stops syncing

These are the issues that Keith Thomas identifies most often during on‑site visits:

• Incorrect account password

• Microsoft 365 authentication issues

• Damaged Outlook profile

• macOS keychain conflicts

• Network restrictions

• Outdated Outlook version

• Corrupted user account

• Damaged system files

Quick checks you can do yourself

These steps solve around 60% of Outlook syncing issues.

Check 1 – Restart Outlook

Fully quit Outlook and reopen it to refresh syncing.

Check 2 – Restart the Mac

A restart resets Outlook and network services.

Check 3 – Check your password

Outlook often stops syncing after password changes.

Check 4 – Update Outlook

Microsoft frequently releases fixes for syncing issues.

If Outlook shows “Not Connected”

This usually means:

• Network issue

• Authentication failure

• Microsoft 365 outage

Try:

• Restarting the Mac

• Turning Wi‑Fi off and on

• Signing out and back into your Microsoft account

If Outlook won’t send or receive emails

This usually means:

• Incorrect password

• Damaged Outlook profile

• Server connection issue

Try:

• Removing and re‑adding the account

• Restarting the Mac

• Updating Outlook

If Outlook sync is slow

This usually means:

• Large mailbox

• Background apps using bandwidth

• Server throttling

Try:

• Closing apps like OneDrive, Dropbox, Zoom and Teams

• Restarting the Mac

• Leaving Outlook open for a few hours

If Outlook keeps asking for your password

This usually means:

• Keychain conflict

• Authentication token expired

• Microsoft 365 login issue

Try:

• Removing old passwords from Keychain

• Restarting the Mac

• Signing out and back into your Microsoft account

If Outlook issues started after a macOS update

This usually means:

• Outlook profile corruption

• Keychain reset

• Network settings reset

Try:

• Updating Outlook

• Restarting the Mac

• Re‑adding the email account

If Outlook works on another user account

This usually means:

• Corrupted user account

• Damaged Outlook preferences

• Permissions issues

Try:

• Testing Outlook on another user account

• Restarting the Mac

• Reinstalling macOS without erasing data

When DIY stops working

You should get on‑site help if:

• Outlook refuses to sync at all

• Outlook profile is damaged

• macOS reinstall does not fix the issue

• Outlook crashes or freezes during sync

• You need your data preserved

These issues usually require:

• Outlook and Microsoft 365 configuration repair

• macOS recovery

• Data‑safe macOS reinstall

• User account repair

• Permissions and system file diagnostics

On‑Site Apple Mac Support – London & South East UK

If Outlook for Mac is not syncing, Keith Thomas provides an often same‑day on‑site support service across:

• Central London

• West, North, South and East London

• Surrey

• Berkshire

• Hampshire

• Wiltshire

Keith Thomas is a Mac Support Specialist in:

• Outlook and Microsoft 365 issues

• Email account configuration

• macOS configuration repair

• Data‑safe macOS recovery

• macOS reinstall and repair

• New Mac setup and migration

• User account and permissions diagnostics

Book on‑site help in London and the South East UK

If Outlook for Mac is not syncing, Keith Thomas can visit your home or office and get you working again.

Keith Thomas – Apple Mac Support Specialist

Established 2010 – Open 09:30–20:30, 7 Days

Contact Keith Thomas by Telephone: 07800 940756 or by Text to: 07800 940756, or simply complete an online website contact form 24/7