Outlook Sync Error 80004005 Exchange ActiveSync: How to Fix It
People experiencing Outlook sync error 80004005 Exchange ActiveSync may find that emails, folders, calendars, or contacts are not updating correctly. Outlook may show the message “The operation failed”, or a manual folder update may fail with error 0x80004005.
The important thing to understand is that this error can refer to more than one problem. In some cases, it is a current Microsoft 365 or Outlook folder-synchronization issue. In other cases, it appears because Outlook is being configured to connect to an Exchange Server through Exchange ActiveSync, which Outlook desktop does not support for Exchange Server connections.
What Does Outlook Error 0x80004005 Mean?
Outlook error 0x80004005 is a general error code that can appear when Outlook cannot complete an operation. When it appears during synchronization, Outlook may be unable to update a folder or download the latest mailbox changes.
If the error message mentions Exchange ActiveSync, the issue may be related to the connection method rather than only the Outlook profile or internet connection. Microsoft states that Outlook desktop does not support connecting to an Exchange Server by using Exchange ActiveSync. Outlook should connect through the standard Exchange connection settings instead.
Why Does Exchange ActiveSync Show a Sync Error?
The Outlook sync error 80004005 Exchange ActiveSync can occur due to different reasons. Some of the common causes are described below –
- Outlook is configured to use Exchange ActiveSync for an Exchange Server mailbox.
- The account was added with the wrong account type or connection method.
- Outlook folders are not updating because of a Microsoft 365 service issue.
- The Outlook profile or cached data has become damaged.
- Cached Exchange Mode is not working correctly.
- An email folder contains an item that Outlook cannot synchronize.
- The mailbox or folder has a synchronization conflict.
- The device or mailbox is blocked by an Exchange ActiveSync policy.
- Autodiscover or the Exchange ActiveSync virtual directory is not working correctly.
- The network connection is unstable.
- Outlook or Microsoft 365 requires an update.
Microsoft has documented a known folder-synchronization issue in classic Outlook in which updating a folder can produce error 0x80004005. Microsoft marked that issue as fixed through a server-side rollout, but organizations that still see the problem on an affected server build may need to contact Microsoft Support.
First Check the Connection Type
Before trying advanced fixes, check whether you are using Outlook desktop, Outlook on the web, or Outlook for iOS or Android.
- Outlook desktop: Do not configure an Exchange Server mailbox through Exchange ActiveSync. Use the standard Exchange account setup.
- Outlook for iOS or Android: Exchange ActiveSync can be used by mobile clients when the organization allows it.
- Outlook on the web: This uses a browser connection and does not require the same desktop profile settings.
If you are using Outlook desktop and the error specifically says that the Exchange ActiveSync server cannot be found, remove the incorrect account and add it again as an Exchange account. Microsoft recommends using standard Exchange connection settings for Outlook desktop.
If Outlook still cannot connect to the mail server, see our guide on Outlook cannot connect to server for additional solutions.
How Can I Fix Outlook Sync Error 80004005?
To fix Outlook sync error 80004005, follow the directions described below. Start with the simple methods and then use the account or profile methods if the issue remains.
1. Restart Outlook and the Computer
At first, close Outlook completely and restart the computer. Temporary Outlook or Windows services may prevent the mailbox from synchronizing correctly.
- Save any open work.
- Close Microsoft Outlook.
- Wait for a few seconds.
- Restart the computer.
- Open Outlook again.
- Select Send/Receive and choose Update Folder or Send/Receive All Folders.
If the same folder immediately shows error 0x80004005, continue with the next method.
If Outlook continues to have synchronization problems, see our guide on Outlook sync issues for additional troubleshooting steps.
2. Check Outlook for a Known Service Issue
If several folders are not updating or many users in the organization are experiencing the same problem, the issue may be on the Microsoft 365 or Exchange service side rather than on one computer.
Microsoft has reported a folder synchronization issue in classic Outlook where using Send/Receive > Update folder returned error 0x80004005. Microsoft stated that a server-side fix was being rolled out and that the issue was fixed in later server builds.
- Ask your Microsoft 365 administrator whether other users are affected.
- Check the Microsoft 365 service health dashboard if you are an administrator.
- Install available Office updates.
- Contact Microsoft Support if the issue continues across several users or server builds.
Do not make major profile or server changes before checking whether Microsoft has already identified the problem as a service issue.
3. Update Microsoft Outlook
An outdated Outlook version may create synchronization and compatibility issues. To update Outlook, follow the directions described below –
- At first, open Microsoft Outlook.
- Tap the File option.
- Select Office Account or Microsoft 365 Account.
- Tap Update Options.
- Select Update Now.
- Restart Outlook after the update is completed.
You should also install available Windows updates and restart the computer.
4. Repair the Outlook Account
Classic Outlook may provide a Repair option for an account profile. This can refresh some account settings without creating a completely new profile.
- Open Microsoft Outlook.
- Tap File.
- Select Account Settings.
- Again, select Account Settings.
- Choose the affected Exchange account.
- Tap Repair if the option is available.
- Follow the on-screen instructions.
- Restart Outlook and check the folder synchronization.
The available options can vary according to the Outlook version and account type.
5. Turn Cached Exchange Mode Off and On
Cached Exchange Mode stores a local copy of mailbox data so that Outlook can continue working when the connection is unavailable. If the local cache is damaged, synchronization may fail.
Before changing this setting, confirm that all important messages and calendar items are available in Outlook on the web or another trusted mailbox view.
- Close Outlook.
- Open Control Panel.
- Select Mail.
- Tap Email Accounts.
- Select the Exchange account.
- Tap Change.
- Clear the Use Cached Exchange Mode option.
- Select Next and then Finish.
- Open Outlook and test the account.
If the error disappears, the local cached data may have been involved. However, Cached Exchange Mode is useful for many users, so ask your administrator before leaving it disabled permanently.
6. Create a New Outlook Profile
A damaged Outlook profile can cause mailbox folders to stop synchronizing. Creating a new profile can help determine whether the problem is limited to the existing profile.
- Close Outlook.
- Open the Windows Search box.
- Type Control Panel and open it.
- Select Mail.
- Tap Show Profiles.
- Select Add.
- Enter a name for the new profile.
- Add the Exchange account using the standard Exchange setup.
- Select Prompt for a profile to be used or set the new profile as the default.
- Open Outlook with the new profile and check synchronization.
Do not delete the old profile until you confirm that the new profile works and any local Outlook data has been backed up.
7. Remove and Add the Account as Exchange
If Outlook desktop was configured to use Exchange ActiveSync, remove that account and add it again using the standard Exchange account type.
- Open File > Account Settings > Account Settings.
- Select the affected account.
- Tap Remove.
- Confirm the action.
- Restart Outlook.
- Select File > Add Account.
- Enter the email address.
- Follow the sign-in window provided by Microsoft or your organization.
- Make sure that Outlook adds the account as Exchange, not Exchange ActiveSync.
- Wait for the mailbox folders to synchronize.
Microsoft states that Outlook desktop does not support connecting to an Exchange Server through Exchange ActiveSync. The correct solution is to use the standard Exchange connection settings.
Before removing the account, confirm that important local messages, contacts, calendar entries, and data files are backed up.
8. Check Outlook on the Web
Open Outlook on the web and sign in to the same account. This helps you determine whether the issue is limited to the desktop application.
- If the messages and folders are correct on the web, the problem may be related to the Outlook desktop profile, cached data, or local account setup.
- If the same folders are missing or incorrect on the web, the problem may be related to the mailbox, server, policy, or synchronization service.
- If only one folder fails to update, note the folder name and the time of the error before contacting your administrator.
9. Check the Sync Issues Folder
Outlook may record synchronization details in the Sync Issues folder. The folder can help identify whether the problem involves a particular message, folder, or connection.
- Open the folder list in Outlook.
- Find Sync Issues and its related subfolders.
- Check the latest error message.
- Note the folder name, time, and item mentioned in the message.
- Do not delete the messages until you have recorded the details.
Some Sync Issues messages are only diagnostic notices and may not represent a continuing problem. If normal folders remain out of date, continue troubleshooting the profile or contact your administrator.
10. Check Exchange ActiveSync on Mobile Devices
If the problem occurs in Outlook for iOS or Android, the administrator may need to check Exchange ActiveSync connectivity, Autodiscover, account authentication, device policies, and mailbox access.
Microsoft’s Exchange troubleshooting workflow includes checking whether the device can create a profile, connect to the server, synchronize email, and update calendar data. It also includes testing Autodiscover and checking whether the mailbox or device is blocked by an ActiveSync policy.
Mobile users should try the following basic steps:
- Update the Outlook mobile application.
- Confirm that the account password is current.
- Switch between Wi-Fi and mobile data.
- Remove and add the account again in Outlook mobile.
- Check whether the account works in Outlook on the web.
- Contact the organization’s administrator if the device is blocked or quarantined.
Do not change Exchange ActiveSync policies yourself unless you are the authorized administrator.
11. Check Mailbox and Device Policies
For an organization using its own Exchange Server, the administrator may need to check the following settings:
- Whether ActiveSync is enabled for the mailbox.
- Whether the device is blocked, quarantined, or allowed.
- Whether the account’s user principal name matches the email address.
- Whether the ActiveSync mailbox policy allows the device.
- Whether the ActiveSync virtual directory is available.
- Whether Autodiscover is working correctly.
- Whether the Exchange server certificate is valid.
Microsoft recommends using the Exchange Remote Connectivity Analyzer to test Exchange ActiveSync Autodiscover and connectivity.
These are administrator-level checks. Regular users should contact their Microsoft 365 or Exchange administrator instead of changing server policies or PowerShell settings.
12. What If the Error Happens Only With One Folder?
If only one folder fails to synchronize, the issue may involve a damaged item, a folder conflict, or the Microsoft service issue described earlier.
- Open the folder in Outlook on the web.
- Check whether the latest messages appear there.
- Move or delete a problematic item only if you know it is safe.
- Wait for the server-side synchronization to complete.
- Try Send/Receive > Update Folder again.
- Record the folder name and error details if the problem remains.
If your Outlook inbox is also not updating correctly, see our guide on Outlook inbox not updating for additional troubleshooting steps.
Do not delete important email or calendar data only to test a synchronization problem.
Frequently Asked Questions
What does Outlook error 0x80004005 mean?
Outlook error 0x80004005 is a general operation or synchronization error. It may occur when a folder cannot update, a local Outlook profile has a problem, or a server-side mailbox issue prevents synchronization.
Does Outlook support Exchange ActiveSync?
Outlook mobile apps can use Exchange ActiveSync when the organization and server allow it. However, Microsoft states that Outlook desktop does not support connecting to an Exchange Server through Exchange ActiveSync. Outlook desktop should use the standard Exchange connection settings.
How do I fix Exchange ActiveSync not syncing in Outlook desktop?
Remove the account from Outlook desktop and add it again as an Exchange account using the standard sign-in process. Do not configure the Exchange Server mailbox as Exchange ActiveSync.
Why are my Outlook folders not updating?
Folders may not update because of a damaged local cache, Outlook profile issue, account configuration problem, server-side synchronization issue, or a particular mailbox item that cannot synchronize.
Can Cached Exchange Mode cause error 0x80004005?
A damaged local cached data file can contribute to synchronization problems. You can test the issue by turning Cached Exchange Mode off, but back up important local data and ask your administrator before leaving it disabled.
How do I check whether the problem is on the server?
Sign in to Outlook on the web and check the same folders. If the web version is also missing messages or folders, the problem may involve the mailbox, server, policy, or Microsoft 365 service rather than only the desktop application.
Is there a current Microsoft issue related to error 0x80004005?
Microsoft documented a classic Outlook folder-synchronization issue in which updating a folder produced error 0x80004005. Microsoft stated that a server-side fix was rolled out in later builds. If multiple users still experience the issue, contact the Microsoft 365 administrator or Microsoft Support.
What should I do if Outlook mobile is not syncing through ActiveSync?
Update Outlook mobile, check the account password and internet connection, remove and add the account again, and confirm that the device is not blocked by an Exchange ActiveSync policy. Contact the administrator if the issue remains.
Why does only one Outlook folder show the error?
One folder may contain a synchronization conflict or a message that Outlook cannot process. Check the folder in Outlook on the web, note the error details, and avoid deleting content until you know what is causing the problem.
Conclusion
By following the above-mentioned steps, you can troubleshoot Outlook sync error 80004005 Exchange ActiveSync. At first, identify whether you are using Outlook desktop or Outlook mobile. If you are using Outlook desktop with an Exchange Server account, do not use Exchange ActiveSync. Remove the account and add it again using the standard Exchange connection settings.
If the issue is related to folders not updating, restart Outlook, install available updates, check Outlook on the web, repair the account, create a new profile, or test Cached Exchange Mode. If multiple users are affected, check the Microsoft 365 service status or contact the administrator because the problem may be server-side.
For Outlook mobile and on-premises Exchange environments, the administrator may need to check Autodiscover, ActiveSync policies, mailbox access, device restrictions, and server connectivity. Do not change Exchange policies or server settings unless you are authorized to manage the organization.
This article is for general information and does not represent Microsoft or any email service provider.