Summary: Outlook stores and synchronizes IMAP mailbox data, such as emails, contacts, attachments, etc., from the local cache to the mailbox server and vice-versa. It maintains a local cache in .ost file format for IMAP accounts, allowing quick access and ensuring consistent Outlook performance even when the system is offline. But sometimes, Outlook IMAP users may experience synchronization issues that can lead to severe problems, such as send/receive errors, missing or inconsistent number of emails, IMAP folders not syncing, etc. In this blog, we discussed methods to fix IMAP sync issues in Outlook 2019, 2016, and 2013 and restore missing email items using an OST to PST Converter tool.
When configured with an IMAP-based email account, Outlook creates an OST Outlook data file to store an offline synchronized copy of mail items, such as emails, contacts, attachments, notes, tasks, etc. Any changes made, such as drafting a new email or deleting messages, etc., are stored in the Offline OST file and synchronized with the mailbox server.
With proper settings and configuration, the synchronization between the Outlook client and mailboxes server ensures uninterrupted email flow. But sometimes, you may experience synchronization issues in Outlook that can lead to errors and prevent users from sending or receiving new emails.
The Synchronization errors and issues in Outlook 2019, 2016, or 2013 usually occur due to damaged or corrupt Outlook data files, i.e., OST (Offline Storage Table).
However, the Sync issues in the Outlook IMAP account may also arise due to the following reasons,
- Oversized or large OST file
- Faulty or incompatible Add-ins
- Corrupt Outlook mail profile
- Hardware or software issues
- Lack of permissions
- Network issues
Due to slow or no synchronization between the Outlook client and mailbox server, users may experience problems, such as,
- Failure in sending or receiving new emails
- Mismatch in number of emails between Outlook and webmail
- Sync errors while manually synching the mail items from IMAP OST to the mailbox server
Thus, fixing the IMAP Sync Issues is critical.
NOTE: Security Updates KB2837618 or KB2837643 cause problems, such as synchronization issues in the Outlook IMAP account. Check your system for these security updates and uninstall them. The updates were released back in 2013.
Methods to Resolve IMAP Sync Issue in Outlook 2019, 2016, or 2013
Below we have discussed some methods to troubleshoot and fix Outlook 2019, 2016, or 2013 Sync Issues. Follow these methods in the given order.
Method 1: Check Network Connection
Synchronization requires an active network connection with the mailbox server. An unreliable and poor network connection or firewall settings can obstruct Outlook from synchronizing the mail items stored in the IMAP OST file to the mailbox server.
Similarly, if the mailbox server is down, it can prevent Outlook from synchronizing the mail items.
To troubleshoot the issue, try reconnecting the network cable or WLAN. Then check the internet connection and firewall settings. You may also contact your IT support to ensure a network firewall isn?t blocking the mail server.
Also, log in to your email account using a web browser to ensure your account is active and the server is available.
Method 2: Create a New Outlook Profile
By creating a new Outlook profile, you can replace your corrupt Outlook profile and fix Outlook IMAP Sync Issues.
The steps to create a new profile in Outlook 2013, 2016, or 2019 are as follow,
- Go to Control Panel and click on Mail.
- Click on the ?Show Profiles? button and click Add.
- Type your new profile name and click OK.
- Configure your IMAP email account and then click Next> Finish.
- Choose ?Always use this profile? in the Mail control panel and then select your new profile from the drop-down.
- Click ?OK? and restart Outlook.
Method 3: Change the Root Folder Path for an IMAP account
Sometimes Outlook may fail to detect the default root folder path. In such case, you can manually set the root folder path for your IMAP account by following these steps,
- In Outlook, go to File
- Then Click on Account Settings > Account Settings and double click on your IMAP email account.
- Click on the ?More Options?? and then click on the ?Advanced? tab.
- Root folder path should display ?INBOX.? If not, enter Inbox and click ?Save.?
- Click ?OK? to exit windows and then restart Outlook.
- After restart, click the ?Send/Receive tab and click ?Update Folder.? Then, wait for the synchronization to finish.
Method 4: Subscribe Folders
In the Outlook IMAP account, you can choose or subscribe mail folder that you wish to synchronize. This can fix Outlook sync issues you face with any particular email folder. The steps are as follow,
- Open Outlook, right-click on your IMAP email account in the left pane and choose IMAP Folders.
- Click ?Query.? This will display all folders in ?All? and ?Subscribed? tabs. Ensure folders are in both matches and have mail folders you want to synchronize.
- Subscribe to any unsubscribed folder and click ?OK.?
Method 5: Rebuild Outlook Data File (OST)
If the methods discussed earlier do not work or fix the Outlook IMAP Sync Issues, it indicates a problem with the OST file. To fix this, you must rebuild the default IMAP OST file.
The steps are as follow,
- In Outlook, go to File>Account Settings>Account Settings and click on the ?Data File? tab.
- Choose the IMAP email account and click ?Open file location?.? This opens the folder location where default OST is stored.
- Close the Outlook app and back up the default OST file to a safe location. Then delete the OST.
- Restart Outlook. This will create a new OST file.
Outlook will start and synchronize the mail items. This should fix the Outlook 2019, 2016, 2013 IMAP Sync Issues.
Conclusion
Sync Issues in Outlook are common and may occur for various reasons, as discussed in this blog post. We have also discussed various methods to troubleshoot and fix Outlook IMAP Sync Issues and resolve the synchronization errors. By applying these methods, you can fix the sync issues and synchronize all your mail items from the local OST file to/from the mailbox server.
But if you find missing items after fixing the synchronization issues in your Outlook client, convert the backup OST file to Outlook importable PST using an OST to PST converter tool, such as Stellar Converter for OST. You can then import the converted PST file to your new IMAP OST file via Outlook Import Export wizard and restore the missing mail items.
