Why IMAP Folder is Not Properly Syncing?

  Mohit Kumar Jha
Written By Mohit Kumar Jha
Anuraag Singh
Approved By Anuraag Singh
Modified On September 11th, 2025
Reading Time 7 Min Read

Recently, you have configured an IMAP account in your email client. But, due to some errors, your IMAP folder is not syncing. This is a common issue, and to resolve it. I am going to help you provide solutions and an alternative option. So, read the article to the end.

As you know, IMAP is an Internet Message Access Protocol, a standard email protocol that is responsible for syncing your email messages across all devices. This protocol allows you to access your folders on your phone, desktop, or webmail. It is very helpful in modern email services as it helps you manage your emails.

But many users run into the problem where their important IMAP folders are not syncing or stop updating. That’s why, here I am to help you in this situation by providing you with solutions. But, before that, let’s understand the cause of the issue.

Factors that Cause IMAP Folders to Stop Updating

When you are dealing with any problem, it is important to understand the reasons behind the issues. Below are some causes that contribute to the problem.

  • You are using the wrong server settings that prevent the email client from connecting and syncing your folder.
  • During the synchronization of IMAP folders, the internet connection is unstable, or there is a problem with the network.
  • You are using an outdated email application that fails to update folders after the configuration changes.
  • Some email clients require subscribing to specific folders. If you didn’t subscribe to it, then the application won’t appear.
  • A large mailbox or the server storage is about to reach its limits may block folder syncing. Some servers also restrict folder depth or the special characters in folder names.
  • Antivirus or VPNs can interfere with the connection between your email client and server.
  • If your local email data or cache is corrupted, then it prevents the folders from syncing.

These are the common reasons why the IMAP folder is not syncing. To resolve the IMAP issue, I will explain different solutions in the upcoming section of the article.

Check IMAP Settings & Update It

Incorrect IMAP settings are the common reasons why your IMAP emails or folders are not working. So, ensure that it is properly enabled and enter the correct IMAP settings. If you don’t know how to see the IMAP settings. Below are the steps.

  1. Open any email application, then go to the Settings.
  2. Choose your account and then Account Settings.
  3. Check if the Incoming Mail server is IMAP or not. If it is not, enable the IMAP option.

These a general steps to check your IMAP settings in any email application. With the help of this, you can also ensure that the server settings are properly configured or not.

Re-Subscribe IMAP Folders in Email Client

Not all email applications sync all your IMAP folders. There are some programs where you need to subscribe to specific IMAP folders. Below are the steps to fix Outlook IMAP folders issue.

  1. If you are using Outlook, go to your IMAP Accounts.
  2. Right-click the top folder of the IMAP account and click on the IMAP Folders option.
  3. Select the Query option and then find the folders you want to see.
  4. Choose these folders, and click on the Subscribe option. Press the OK button.

For Thunderbird

  1. In the application, right-click on the IMAP account name.
  2. Click on the Subscribe option, and you will see a list of folders.
  3. Check the box next to the folders you want. Hit OK.

For Apple Mail

  1. Log in to Apple Mail, then click on the Mail option.
  2. Select the Preferences and click on the Accounts button.
  3. Choose your email account, and click the Advanced tab.
  4. Ensure IMAP path prefix is set correctly.
  5. After that, close the Preferences menu and restart Apple Mail.
  6. Then, go to the View menu bar, choose Show Mailboxes to see the IMAP folders.

Clear Email Client Cache Data

Every email client stores a local copy of emails, folder structure, and settings in a cache. The purpose of a cache is to load your message faster and decrease repeated downloads from the server. But, over time, these data become corrupted and create conflict with server data and causing your IMAP folders not to sync properly. So, if you are facing issues like this, remove the cache data by following the steps.

In Outlook

  1. First of all, close your Outlook application.
  2. Then, go to the location of your OST file.
  3. In the file, search for your account’s OST file and rename it. You can add .old at the end.
  4. After that, reopen your program. The program automatically creates a new OST file and resyncs your IMAP folder.

For Thunderbird

  1. In Thunderbird, choose the folder that you want to clear the cache.
  2. Right-click on the folder and select the Properties button.
  3. Click on the Repair Folder button to rebuild the local cache for your folder.
  4. To reset the folder, close Thunderbird and go to the Thunderbird profile folder.
  5. Delete the ImapMail folder.

Monitor IMAP server Status & Connectivity

A stable connection between your email client and email server depends on the syncing of your IMAP folder. If the server is down and you are experiencing issues, the problem IMAP folder is not syncing occurs. So, check the status of your IMAP server follow the steps below.

  1. First, check the internet connection. Make sure that your device is connected to a stable network bandwidth.
  2. Then, go to your email provider’s status page or support site to check if there are any ongoing outages or maintenance.
  3. Try to access your IMAP email using webmail. If the folder is visible, then. The problem is with the email client.
  4. Restart your device or router to resolve any temporary issues.

If these methods do not work, then contact the support team of your email provider. So, here are the solutions you solve the problem of the IMAP folder not syncing. While these solutions work, there is are chance that it will happen again. To avoid that, you have to take some precautionary steps.

Preventive Steps to Secure IMAP Folders

  • It is very important to regularly clean your folder. If the IMAP folder is overloaded, then it will slow down the synchronization problem.
  • Make sure you regularly update your email applications. So that you can avoid any syncing errors, and it will ensure your stability.
  • When you are rearranging folders or moving large emails, don’t do it directly from the server. Because sometimes this causes conflicts in the email client.
  • Also, it is crucial to have a stable internet connection when you are syncing your IMAP folders.

By following these preventive steps, you can prevent any issues regarding IMAP emails. There is another way that can help you in this situation, which is backing up your IMAP emails.

Backup IMAP Folders to Prevent the Issue

When your IMAP folder fails to sync, this could lead to missing or inaccessible emails. But if you take a backup of your folder’s data. Then you can access your data. For this, try SysTools IMAP Backup Tool, a professional software that can easily save any IMAP folders in your account. The software helps you not only in this situation but in many cases, where you can retain your deleted IMAP emails from the server securely.

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To Conclude

In this article, I have explained various ways to solve IMAP folders are not syncing. These methods help you in the synchronization process. If this does not work, you can contact your email provider. After that, it is also important to secure your IMAP folder to prevent this issue from happening in the future. So, properly follow the above steps and backup your data from IMAP folders.

  author

By Mohit Kumar Jha

Mohit is a Microsoft Certified expert for all things Microsoft. He brings a unique perspective gained from nearly a decade of active participation in various IT forums, blogs, and social media. Known in admin circles as the go-to guru for solving user queries in the domain of cloud migration, data backup, and digital forensics. The secret to his core expertise lies in solving problems practically. Through this hands-on experience, he has acquired knowledge in diverse domains like Microsoft 365 Cloud, On-Premise Exchange Server, AD, and Entra ID.