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How to Fix - "Outlook 365 Stuck at Updating Inbox and Outbox"?

Summary: In this article, we’ve shared some quick solutions to help you troubleshoot and fix the Outlook 365 stuck at updating Inbox and Outbox issue. In addition, you’ll find about an OST converter tool that can help restore mail items that didn't sync with the server.

Outlook 365 works on two-way synchronization. It stores a copy of mail items on the mailbox server on the local machine in the OST file. The changes made in Outlook are stored in the OST file and synchronized frequently with the mailbox server and vice-versa. However, Outlook cannot update the mail items to or from the mailbox server when synchronization fails. In such cases, users can neither send nor receive emails, leading to Outlook being stuck at updating the Inbox and Outbox folders issue.

The Send/Receive errors in Outlook 365 usually occur due to system crashes, abrupt shutdowns caused by power failure, or any hardware/software-related problem. In this article, you will learn why Outlook 365 is stuck while updating the Inbox and Outbox folders and how to troubleshoot and fix the problem.

Reasons for Outlook 365 Stuck at Updating Mail Folders

Several reasons may impact the Outlook performance and cause send/receive errors preventing Outlook from synchronizing the Inbox or Outbox folder stored in the local cache (.ost) with the mailbox server. Some common reasons are as follows:

  • Problem with the internet connection
  • Incorrect email settings
  • Outlook conflict with other apps, such as Antivirus
  • Faulty or damaged add-ins
  • Corrupt Outlook profile
  • Inconsistent or damaged Outlook data file (.ost)
  • Low mailbox storage
  • Large or oversized local cache (OST)

Solutions to Fix Outlook Stuck while Updating Inbox and Outbox Folders

Follow these solutions to fix the Outlook stuck at updating the Inbox or Outbox folders issue.

1. Check Network Connection

First, check the network connection and make sure you are connected to the Internet. Also, verify that the server is available and the profile is active. For this, you can log in to your Office 365 account via the web. If you can log in and access your emails successfully, it indicates there is an issue with your Outlook client.

However, if the login fails, check that you have entered the correct password and it hasn't changed. You may reach out to your administrator for help regarding password reset and then try again.

Once the system is connected to the Internet and the server is available, follow the next solutions to troubleshoot and fix the problem.

2. Temporarily Disable Antivirus Program

Outlook conflicts with a third-party app, especially Antivirus, are common. If the Antivirus isn't Outlook friendly, you may experience certain issues while using Outlook. An outdated mail folder is one such issue.

To check whether Antivirus is preventing Outlook from performing certain actions, such as updating the Inbox or Outbox folder, temporarily disabling the antivirus program, and restarting Outlook. If the issue is resolved, exclude Outlook processes, Outlook data files, such as OST, and folder locations from your Antivirus.

3. Check Outlook Email Account Settings

You should also check your email credentials and account settings. Incorrect settings may prevent Outlook 365 from synchronizing the Inbox or Outbox folders. To do so, follow these steps:

  • Open Outlook and go to File > Account Settings > Account Settings.

edit Outlook account settings

  • Select the email account and click Change.

select email profile click change

  • Click More Settings.

choose more settings outlook 365

  • Check and verify that all email account settings are correct.

4. Disable IPv6

Some users, who encountered the Outlook synchronization problem where Outlook could not update the Inbox or Outbox folder, resolved the issue by disabling the IPv6 on their Windows PC. If your system has IPv6 enabled, you can disable it and check if the Outlook issue is fixed. The steps are as follows:

  • Open Control Panel and go to Internet > Network and Sharing Center.
  • Click Change Adapter Settings, right-click on the Ethernet or Wireless adapter and choose Properties.
  • Uncheck the Internet Protocol Version 6 (TCP/IPv6) option and click OK.

disable ipv6 protocol

  • Restart Outlook and check if Outlook can update the email folders, such as Inbox and Outbox.

5. Disable Cached Exchange Mode

Toggling Cached Exchange Mode may also resolve the issue if caused by some temporary connectivity problem from the client or server-side. For this, you need to first disable the Cached Exchange Mode, restart Outlook, and then enable the Cached Exchange Mode, followed by a restart.

The steps are as follows:

  • Open Outlook and go to File > Account Settings > Account Settings.

access Outlook 365 email account settings

  • Select your Office 365 email account and click Change.

click change to edit account settings

  • Uncheck the Use Cached Exchange Mode option.

disable cached exchange mode

  • Click Next and then restart Outlook.

The Inbox and Outbox folders should be updated now. After that, you can switch back to Cached Exchange Mode and then check if the issue is resolved.

6. Repair Microsoft Office

You may try repairing the Microsoft Office to fix underlying issues with the Outlook client. The steps are as follows:

  • Open Control Panel and click Uninstall a program.
  • Select Microsoft Office…. from the list and click

control panel uninstall a program

  • Select Repair and click Continue.

repair microsoft office installation

  • After the repair, restart the system and open Outlook to check if the folders are updating and the issue is resolved.

If the repair fails to fix the issue, try reinstalling Microsoft Office.

7. Create a New Outlook Profile

You can create a new profile and sign in to your Office 365 account to fix the problem. Use the profile for a week to ensure the problem is resolved. If the issue doesn't arise with the new profile, you can remove the old profile and keep using the new one for your email communications. The steps are as follows:

  • Close Outlook and open Control Panel.
  • Click Mail > Show Profiles… and then click Add.

show profile outlook 365

  • Type new profile name and click OK.

create new outlook profile

  • Add your email account by entering the Office 365 credentials and following the setup wizard to configure your email profile.

setup email account in new email profile

  • Outlook will connect to the server and start the synchronization. After the sync, check if all the mail folders are updated.

Note: If you find some mail items missing from your new profile, move them to your new profile from the old one. Once all emails are moved, you may remove the old profile, which will also remove the OST file associated with that profile.

8. Rebuild OST File

If the above solutions didn't work out in your case, try rebuilding the offline Outlook data file(.ost), i.e., OST. Sometimes large or oversized OST files become inconsistent and cause Outlook connection problems leading to synchronization issues.

Follow these steps to rebuild the OST Outlook data file and resolve the outdated email folders problem.

  • Press Windows+R, type %localappdata%/Microsoft/Outlook, and press the Enter This will open the default OST file location.
  • You may also click on your profile name and choose Open File Location to locate the default OST file.

choose open file location to access ost file

  • Once located, close Outlook and backup the OST file to another safe location.
  • Then delete the default Outlook 365 OST file.
  • Start Outlook. This will create a new OST file.
  • After creating a new OST, Outlook will synchronize all the mail items. This may take a while to complete depending on your mailbox size.

This should fix the issue and Outlook should be able to update the Inbox and Outbox folders immediately.

However, you should check if all emails are synchronized and available in your new OST file. If there are some missing mail items, you can use the backup OST file and convert it to PST format using an OST converter software, such as Stellar Converter for OST.

Once converted, you can import the missing mail items from the PST file. Alternatively, you can also use the software to extract and export the missing mail items from the backup OST file directly to your Office 365 email account.

Read more, The OST File Has Reached The Maximum Size


Outlook may fail to synchronize changes stored in the OST file or retrieve information from the mailbox server due to problems with the Outlook client, system, or Outlook OST data file. As a result, Outlook may fail to update the Inbox or Outbox email folder. Also, any email sent to you or sent from your Outlook client will not be received or delivered. However, you can follow the solutions discussed in this article to find the cause and resolve this Send/Receive error in Outlook.

Once fixed, you can start sending or receiving new emails. In case of missing emails, you can always use Stellar Converter for OST. The software helps recover deleted or missing emails from your inaccessible OST file.

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