In Microsoft Outlook, the Exchange Server mailbox is already configured. With the help of the OST data file, you can access exchanged mail in offline mode. Whenever the connection is set again with the Exchange Server, it might be possible that the server cannot sync all the mailbox data in the OST data file. As a result, it can lead to issues when a user cannot send and receive email or any folder is not updated. Thus, if you are facing any of these issues, it can be Outlook synchronization issues.
Why Synchronization Fails Between OST File and Exchange Server
The Outlook OST file and Exchange Server mailbox may not be syncing for the following reasons mentioned below:
- Poor internet connection.
- Folders not updated in MS Outlook.
- Faulty Add-ins
- Disabled the mailbox profile.
- Damaged OST or Exchange Server support file.
- New emails not downloaded in Outlook.
How to Fix Synchronization Issues Between OST File and Exchange Server
The following are some solutions that can help resolve the OST file and Exchange Server synchronization issues in Outlook 2013, 2016, and 2019.
Check Whether Offline Folders Are Synchronized
Before moving to the below solutions, first, check whether the offline folders are synchronized or not. Follow the steps below to see if the synchronization is enabled.
- Choose the offline folder and right-click on it, and click on Properties. Then go to the Synchronization tab.
Note: If you do not find the Synchronization tab, it shows you didn’t create the profile for using the offline folders.
- Under the Statistics For this Folder, confirm the following fields:
- Last Synchronized on
- Server folder contains
- Offline folder contains
If the items in the Server folder contains and the Offline folder contains fields that do not look alike, it signifies that the synchronization process is not functioning.
Note: In the offline folder, items will depend upon the Mail to keep offline or Download email for the past setting only.
Check Network Connection
An unreliable or poor network connection can stop the synchronization of mail items between Outlook OST files and the Exchange Server. Before you start troubleshooting, first check your network connection.
Try to plug and unplug the network cable or reconnect to WLAN, and then check your internet connection. Also, you should once check your security software, such as firewall settings that might have stopped Outlook from syncing the OST file with Exchange Server. Now disable firewall settings and log in to your email account to ensure your account is active and the server is available. If it does not happen, then follow the next solution.
Clean Sync Issues Folder
During the synchronization process between Outlook OST file and Exchange Server, it creates a folder name Sync Issues Folder that stores any information in it. Cleaning the contents of the Sync Issues Folder (Conflicts, Local and Server Failures) can help you troubleshoot Outlook sync issues. Follow these steps:
- Open Outlook and click on the three dots present at the bottom navigation pane and select Folders.
- The navigation pane will change, and you will see the mail folder Sync Issues.
- Then expand the Sync Issues folder to see the Conflicts, Local, and Server Failures folders.
- Select all the items in the Sync Issues folder and its sub-folders, and delete them.
- Lastly, close Outlook, restart it again and wait for the synchronization.
Synchronize the Folders
Synchronize the folders if you do not receive email in your Outlook account. Follow the steps below to see how you can fix the sync issue between OST and Exchange Server.
Manual Synchronization
- Select the folder of your choice.
- On the Outlook ribbon, click Send/Receive option and then select Update Folder to start synchronization for one offline folder, or if you want to synchronize all offline folders, then choose Send/Receive All Folders.
- The synchronization process starts, and you’ll see a synchronization status message on your screen.
Note: If you haven’t synchronized the offline folders for a long time and there are many items in your mailbox, the synchronization process will take more than 30 minutes.
Automatic Synchronization
- Go to the File option > Options.
- In the Outlook Options tab, select Advanced.
- Under the Send and Receive section, tick on Send Immediately When Connected.
- Then choose Send/Receive.
- In the Send/Receive Groups tab > Perform an Automatic Send/Receive When Exiting > Close.
- Click on OK.
Learn more : Shared Calendar Not Syncing with Outlook?
Replace the Corrupted Exchange Server Service Support File
If offline folder synchronization is still not working, it might be possible that the MS Exchange Server service support file is corrupted. To do this, you must either rename or remove the file and then replace it with the original service support file. The steps are below:
- Open File Explorer.
- Then locate C:\Program Files(x86)\Microsoft Office\root\Office16 or C:\Program Files\Microsoft Office\root\Office16.
Note: The folder path to the EMSMDB32.dll file will vary, it depends upon the version and bit-value of the Office product installed.
- Right-click on the EMSMDB32.dll file, click on Rename and then add the .old filename extension.
- Replace the Exchange Server service support file
- Click on Start, and select Apps and Features on the menu.
- Then choose the MS Office product you want to repair and then select Modify.
It depends on whether your copy of Office is a Click-to-run-based or .msi-based installation. Follow the steps:
| Click-to-run | MSI |
| In How would you like to repair your Office Programs window > Online Repair > Repair (The Quick Repair option is faster, but it only replaces corrupted files.) | In Change your installation window > Repair > Continue. |
- Now synchronize the offline folders.
Create a New Email Profile
You can create a new email account under the new Outlook profile, it will help you to replace the corrupted file and might also fix the sync issues. The measures are as follows:
- Open Control Panel > Mail.
- Click on Show Profiles > Add.
- Enter a new profile and click OK.
- Then configure the IMAP, Office 365, or Exchange email account, and click Next > Finish.
- Choose Always use this profile and select the newly set up Outlook profile from the dropdown.
- Click OK and then restart Outlook.
Create the OST File Again
If any of the above solutions do not work out, it signifies a problem with the OST data file. To fix this, create a new OST file. The steps are below.
- In Outlook, go to File> Account Settings> Account Settings.
- Click on the Data File tab and then select email account.
- Click on Open file location and after it close the Outlook client.
- Place the OST file in another location.
- Now restart Outlook, and a new OST file is created automatically.
Further, in the process of synchronization between Outlook OST file and Exchange Server, it might happen that some items are missing in your mailbox. You can convert the backup of the OST file into PST by using Stellar Converter for OST, and then you can import the converted PST to your new OST file through Outlook Import Export Wizard.
This software also recovers the OST file that is recreated but fails due to the disabled or deleted mailbox items from the Exchange Server or Microsoft 365. It can even help you move the mailbox items from an inaccessible OST file directly to Live Exchange Server or Microsoft 365.
Conclusion
Synchronization issues between Outlook OST files and Exchange Server can cause differences in the mail items. When the Outlook OST file fails to synchronize the mail items from the Exchange Server, it may display send/receive errors that prevent users from sending or receiving new mail items. In this post, we have discussed various solutions that you may apply to fix the synchronization issue between Outlook OST file and Exchange Server is down.
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