If classic Outlook for Windows isn’t syncing, first check its connection status and whether your mail works in webmail. Those two checks help distinguish an offline Outlook app or local setup problem from an account or provider outage. Then follow the steps for the specific symptom: messages not sending or arriving, missing folders, or calendar and contacts not appearing on a mobile device.
First, confirm which Outlook app has the problem
These steps are for classic Outlook for Windows, the desktop application with the traditional Outlook ribbon. They do not apply identically to new Outlook, Outlook on the web, or Outlook mobile. Microsoft separates its guidance for these versions; see its Outlook for Windows troubleshooting guidance and comparison of new and classic Outlook. If the app is new Outlook or a phone app, use troubleshooting instructions for that app instead.
As an Amazon Associate I earn from qualifying purchases.
Note the exact status message and what is missing: incoming mail, outgoing mail, folders, calendar events, contacts, or address-book entries. Also check whether the same account works in webmail. These details determine which branch to follow.
Check Outlook’s connection and webmail
- Read Outlook’s status bar. Look for “Disconnected,” “Working Offline,” or “Trying to connect.” These messages point to a connection or offline-state issue.
- Check the internet connection. Open an ordinary website. If it will not load, fix the computer’s connection before changing Outlook settings.
- Test the account in webmail. Sign in through your provider’s website. If webmail also fails, contact the email provider or your organization’s administrator. If webmail works, focus on Outlook’s local connection, account setup, or computer software.
- Turn off Work Offline if it is enabled. In classic Outlook, select Send/Receive > Work Offline to toggle it off, then check the status bar again. Microsoft’s connection troubleshooting steps cover this check.
Try a manual send/receive for mail problems
If Outlook is connected but mail is not moving, use the classic Outlook Send/Receive controls to run a manual send/receive. Automatic checking is governed by Send/Receive Groups, so the interval can vary. Do not assume every Outlook version or account has a button called “Sync”: classic Outlook’s controls differ from new Outlook’s, and third-party Gmail, Yahoo, iCloud, POP, and IMAP accounts may not support the same manual Sync button described for other account types. Microsoft explains the distinctions in its account sync guidance.
#1 Best Overall
Check the account type, password, and mailbox
Verify how the account was added
If existing messages or custom folders are missing, confirm that the account was added using the right account type. Microsoft specifically advises adding Hotmail.com or Live.com addresses as Outlook.com, not as Exchange or Microsoft 365. See Microsoft’s Outlook connection troubleshooting and its email setup guidance.
Update credentials when they change
If you changed the password on the provider’s website, update the credentials Outlook uses. Some providers require an app password for mail apps rather than the account’s regular password; check the provider’s instructions if the regular password is rejected.
Look for a full mailbox or a message stuck in Outbox
Microsoft says a full Microsoft cloud storage allowance can prevent sending and receiving. If a message is stuck in Outbox, a large attachment may be blocking it and later messages behind it. Open the oldest stuck message first and reduce or remove its attachment where appropriate. Follow Microsoft’s send-and-receive troubleshooting guidance.
Quick wins for a faster PC:
Repair Windows errors before they cause bigger problemsFix Now →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Isolate add-ins and Outlook profile problems
Test Outlook in safe mode
Start Outlook in safe mode to disable add-ins. If sending or receiving works in safe mode but not during a normal start, investigate the add-ins rather than immediately changing the account or data files. Microsoft’s Outlook troubleshooting steps include safe-mode diagnosis.
Rank #3
- The Microsoft Office 365 Bible: The Most Updated and Complete Guide to Excel, Word, PowerPoint, Outlook, OneNote, OneDrive, Teams, Access, and Publisher from Beginners to Advanced
- ABIS BOOK
Repair Office if the app itself appears faulty
If connection and account checks do not explain the problem, use Windows’ Office repair option. Repairing the Office application is a separate step from repairing an Outlook data file.
Use a new profile as a diagnostic
A new Outlook profile can help identify whether the existing profile is corrupted. If the account works in the new profile, the original profile is implicated; that does not mean every problem requires deleting it. Before removing a profile, protect any content stored only on the computer. Microsoft describes profile and data-file troubleshooting in its Outlook data-file repair guidance.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Repair a PST or OST data file only when needed
Classic Outlook uses PST and OST data files. Microsoft documents the Inbox Repair Tool, SCANPST.EXE, for scanning and repairing Outlook data files; consult its repair instructions before running it.
Do not remove files or profiles casually. Locally cached content can be deleted during profile or file changes, and local-only data may not exist on the mail server. Protect or back up such data before proceeding. Data-file repair is a deeper intervention than checking status, webmail, or add-ins.
If calendar or contacts are missing on a phone
When mail works on a phone or tablet but calendar events or contacts do not appear, treat this as a mobile account or permissions issue—not as proof that the Windows Outlook profile needs repair. Account protocol matters: Microsoft notes that an IMAP account may not sync calendar and contacts.
- Confirm the account type and whether it supports calendar and contact syncing.
- Check the device’s permissions for Outlook contacts.
- Refresh or reset the account using the mobile app’s account settings.
- If needed, remove and add the account again, after confirming that any device-only information is protected.
Microsoft’s Outlook mobile troubleshooting guidance covers these device-side checks. They are not universal desktop Outlook repairs.
Check for a known Outlook issue before major changes
Microsoft maintains a changing fixes and workarounds page for classic Outlook for Windows. Match the listed issue to your Outlook version and exact symptom; a listed issue is not necessarily the cause of a particular sync failure. For organization-managed Microsoft 365 accounts, ask your administrator to check for service, policy, or account issues when local troubleshooting does not resolve the problem.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
