Fix Outlook Stuck on Disconnected or Not Syncing (Classic and New Outlook)

Outlook sits at the bottom showing Disconnected, Trying to connect, or Working Offline, yet your browser loads pages fine and your phone gets the same mail instantly. When the internet works but Outlook will not sync, the problem is almost always local: a toggled Offline mode, a bad add-in, a corrupt local data file, or a stale profile. Here is the order to check, covering both classic Outlook and the new Outlook app on Windows 11.

Key takeaways

• Internet working but Outlook disconnected points to a local cause, not a server outage.
• The very first thing to rule out is Work Offline being accidentally enabled.
• A corrupt OST/PST file or a damaged profile are the most common deeper causes in classic Outlook.
• Add-ins, VPNs, and antivirus mail scanning frequently break the connection.
• New Outlook has fewer knobs; removing and re-adding the account is the main reset.

Step 0: Confirm it is not a real outage

Before touching settings, check the Microsoft 365 service status (or your provider's status page) and try webmail in a browser. If webmail is also down, it is a server issue and you just wait. If webmail works, continue.

This table maps the usual causes to the fix and which Outlook each applies to, so you can jump to the right step:

Cause	Symptom	Fix	Applies to
Work Offline toggled on	Status reads "Working Offline"	Untoggle on the Send / Receive tab	Classic
VPN, proxy, or AV mail scan	Disconnects while browsing works	Disconnect VPN, clear proxy, pause mail scan	Both
Faulty add-in	Connects only in Safe Mode	Disable add-ins, re-enable one by one	Classic
Corrupt OST file	Outlook open but never syncs	Rename the .ost so it rebuilds	Classic
Damaged profile	Disconnects survive every other fix	Create a new mail profile	Classic
Stale token or sync state	Account stuck "not syncing"	Remove and re-add the account	New Outlook
Wrong system clock	Token validation fails	Turn on automatic date and time	Both

Step 1 (Classic Outlook): Turn off Work Offline

This toggle silently disconnects Outlook and is the most common false alarm.

Go to the Send / Receive tab and look at Work Offline. If it is highlighted, click it to go back online. The status bar should change from Working Offline to Connected.

Step 2: Disable VPN, proxy, and antivirus mail scanning

These three intercept Outlook's connection even when general browsing works.

• Disconnect any VPN and test.
• Check proxy settings: Control Panel > Internet Options > Connections > LAN settings, and untick any proxy you do not actually need.
• Temporarily disable your antivirus email scanning add-on, which can stall the secure connection to the server.

Step 3 (Classic Outlook): Start in Safe Mode to test add-ins

A faulty add-in can block the connection entirely.

1. Press Win + R, type outlook.exe /safe, and press Enter.
2. If Outlook connects in Safe Mode, an add-in is the cause.
3. Go to File > Options > Add-ins > Go (next to COM Add-ins), disable everything, and re-enable them one at a time to find the offender.

Step 4 (Classic Outlook): Rebuild the OST file

A corrupt offline data file (.ost) stops syncing while keeping Outlook open.

1. Close Outlook completely.
2. Open Control Panel > Mail > Email Accounts > Data Files, select the account, and note the .ost file path.
3. Browse to that folder and rename the .ost file (for example to archive.ost.bak).
4. Restart Outlook. It rebuilds a fresh OST from the server and resyncs all mail.

Step 5 (Classic Outlook): Create a new profile

A damaged profile causes persistent disconnects that survive every other fix.

1. Go to Control Panel > Mail > Show Profiles > Add.
2. Create a new profile, add your account, and set Outlook to use the new profile.
3. Launch Outlook with the fresh profile and test.

Step 6 (New Outlook): Remove and re-add the account

The new Outlook app has fewer settings, so the reliable reset is re-adding the account.

• Go to Settings (gear) > Accounts > Email accounts, select the account, and Remove.
• Re-add it under the same menu and let it re-sync. This clears the stale token or sync state behind most "not syncing" cases in the new app.
• Also confirm automatic date and time is on, since a wrong clock breaks token validation, the same issue covered in our Microsoft Store download guide.

Step 7: Run the Get Help troubleshooter

Windows 11 ships an automated Outlook connectivity fixer. Open the Get Help app and search Outlook disconnect, then run the guided troubleshooter. It checks profile, connectivity, and cached-mode settings and applies common fixes for you.

What to do right now

Work the fixes in the order that resolves the most cases for the least effort:

• Confirm webmail loads in a browser so you know it is not a server outage.
• In classic Outlook, check the Send / Receive tab and turn off Work Offline if it is highlighted.
• Disconnect any VPN, clear unneeded proxy settings, and pause antivirus mail scanning, then test.
• Start Outlook in Safe Mode (outlook.exe /safe); if it connects, disable add-ins and re-enable one at a time.
• If it still fails, rename the .ost file so Outlook rebuilds it, or create a fresh mail profile.
• In the new Outlook app, remove and re-add the account, and confirm automatic date and time is on.
• If you are stuck, run the Get Help app's Outlook disconnect troubleshooter.

Why the order matters

It is tempting to jump straight to rebuilding the data file or making a new profile, but those are heavier steps that take longer and occasionally surface their own quirks. The early steps, ruling out a real outage, the Work Offline toggle, and VPN or antivirus interference, clear the majority of "disconnected while the internet works" cases in under two minutes. Saving the OST rebuild and profile rebuild for last means you only reach for them when the quick checks have genuinely failed, which is rare. Treat the list as a funnel, not a menu.

Frequently asked questions

Why is Outlook disconnected when my internet clearly works?

Because Outlook's connection to the mail server is separate from general browsing. A VPN, proxy, antivirus mail filter, bad add-in, or corrupt local file can break Outlook's secure channel while web pages still load. The local fixes above target exactly that gap.

Will rebuilding the OST lose my email?

No, for accounts that sync from a server (Exchange, Microsoft 365, IMAP). The OST is just a local cache; renaming it forces a clean re-download from the server. The caution is PST files, which can hold the only local copy, so never delete those.

The new Outlook keeps reverting to classic, or vice versa. Does that matter for syncing?

The two apps store profiles and data separately. If you switched apps and lost mail or sync, make sure the account is added in the app you are actually using, and re-add it there. Settings from one do not carry to the other. If you are deciding which to stay on, our comparison of new Outlook versus classic Outlook lays out the trade-offs.

Could a recent password change cause this?

Yes. After changing your account password, Outlook may keep trying the old credentials and show Disconnected. Re-enter the new password when prompted, or remove and re-add the account so it re-authenticates cleanly.

Quick recap

Confirm webmail works, then turn off Work Offline and disable VPN, proxy, and antivirus mail scanning. In classic Outlook, test add-ins in Safe Mode, rebuild the OST, or create a new profile. In new Outlook, remove and re-add the account, and run the Get Help troubleshooter if needed.