Learn to fix the “Cannot Expand the Folder” error

Read time 10 minutes

MS Outlook has become the go-to application for all professionals to prioritize all their email and data management needs. It enables you to manage your emails, contacts, calendar, and to-do lists. Although it has lots of essential features, it is not immune to technical glitches. Occasionally, users have experienced trouble while opening certain PST folders. If you have similar issues where you cannot open or expand the folder in the Outlook application and want a solution to fix it, then reading the blog is a must for you.

In this blog, we are going to explain the best solutions to fix the error and let you access the folder again to carry on with your work.

The error message that pops up is:

“Cannot expand the folder. The set of folders cannot be opened.“

Why does the error “Cannot expand the folder” occur?

The error is common in Outlook 2010 or later versions to the extent that thousands of users have complained. It usually occurs when an Outlook user attempts to expand the shared folder, public folder, Address Book, or another secondary mailbox from the interface. Instead of expanding the respective folder, the error displays:

“Cannot expand the folder. The Set of Folders cannot be opened. “
or
“Cannot expand the folder. Microsoft Outlook cannot access the specified folder.“

Let’s discuss the possible reasons for the occurrence of this error.

Reasons that are responsible for the “Cannot expand the folder” error

• Exchange Cached mode is “ON”
• Interference of third-party add-ins.
• Corrupt Outlook profile
• OST/PST file corruption
• Microsoft Office application issue.
• Folder visible permission is not set.
• Issue with network

Instant Solution

Try the automated tool Kernel for OST to PST Converter to Convert OST File to PST, EML, MSG, Office 365, and Exchange.

• Backup OST data to PST
• Search specific items within OST
• Repair corrupt OST and NST files

Free Download 100% Secure

Try these simple solutions to fix or resolve the “Cannot expand the folder” error on your own.

Solution 1: Make the folder “Visible”
Solution 2: Disable the cached mode
Solution 3: Disable Microsoft Outlook Add-ins
Solution 4: Create a new Outlook profile
Solution 5: Repair the Outlook application
Solution 6: Repair the Outlook database files
Solution 7: Using the Microsoft Support & Recovery Assistant (MSRA) Tool
Here is the complete explanation of the above-mentioned solutions with their entire process.

First, make sure that there are more subfolders than the limit. Earlier, the limit was 5000, but later, Microsoft increased the folder limit. Now, 5000 items per calendar folder and 100000 items per folder are allowed. Then check if the permission for the .ost folder view is assigned or not.

1. Open Outlook , right-click on the troubling folder and click on the Properties option.
2. Now, move to the Permissions tab and make sure that “Folder Visible” permission is assigned.
3. If not, click on the Edit option and assign the same. Click OK to save the settings.
4. Now, check whether your problem is resolved.

Cached Exchange Mode saves a copy of the mailbox to the user’s computer. It provides you the facility to access all the data. But when the cached mode is on, it may cause trouble in expanding the respective folder due to synchronization issues. Therefore, it is suggested to disable the cached Exchange mode in Outlook in such a situation. Follow the simple process to do so:

1. On your Outlook interface, navigate to File > Account Settings > Account Settings.
   
2. Click on the Email section, double click on the to open the Change Account page. Uncheck Use Cached Exchange Mode option and click on the Next
   
3. Now, restart the Microsoft Outlook application and try to expand the folder.

Conflicts with third-party add-ins can affect the synchronization of the mailbox as well as the functioning of the application, as they become roadblocks to a smoothly running function. Running the application in Safe Mode might also help to resolve the issue. You can also try disabling the Outlook add-ins using the following procedure and then attempt to expand the problematic account folder.

1. Open Outlook and tap on the File > Info > Options.
   
2. Click on the Add-ins.
3. Now unselect the Add-ins and click on OK.
   
4. Restart the Microsoft Outlook application, and then try to expand folder again.

Due to some bugs, errors, or other issues, the application might get corrupted. Taking it as a solid reason behind the issue, you can try performing an online repair on your Microsoft Office application suite. But before you begin with it, make sure you have a strong network speed to perform the repair. Follow the given procedure to repair the Outlook application.

1. Go to the Control Panel and click on the Programs and Features option.
2. Move to the installed Microsoft Office program and right-click on it. Select the Change option from the drop-down list.
   
3. Select Quick Repair and click on Repair option.
4. Follow the next instructions to perform the repair.
5. Once the repair is completed, try accessing the folder from the Outlook application.

A corrupt Outlook profile is another major cause of the “Cannot expand the folder” issue. It can be resolved by creating a new Outlook profile and set it as the default one will give you a clean and bug-free start. and the corruption-containing profile will be deleted for good.

Perform the following steps to create a new Outlook profile-

1. Go to the Control Panel and click on the Mail option.
2. On the Mail Setup dialogue box, click on the Show Profiles option.
3. Click Add to add a new profile. Then create the new one and click OK.
4. Check Always use this profile and choose the new account from the drop-down list. Then, click on OK.
5. Now, launch the Outlook application with the new profile and check either the problem is resolved or not.

To resolve the “Outlook cannot expand the folder” error in Microsoft Office applications, you need to download & install the Microsoft Support & Recovery Assistant (MSRA) tool on the affected system.

1. Upon successful installation, launch the MSRA tool & accept the license agreement by clicking on the “I agree” button.
2. In the MSRA tool window, locate the “Outlook” option & select it, & then click on the “Next” button to proceed.
3. Now, select the “Outlook won’t start or other problems” option & tap on the “Next” button again.
4. When prompted, confirm that you are experiencing the issue with Outlook by selecting “Yes,” & then click on the “Next” option.
5. Furthermore, follow the instructions on the MSRA wizard to diagnose & resolve the “Outlook cannot open set of folders” issue.

The corrupt .ost file can be a reason for the error, but here you have an advantage that you can anytime recreate the OST file of your configured Exchange Server account. You just require opening the .ost file location from the Account Settings in Outlook and then deleting the problematic .ost file from there using the Delete option simply.

The default location of the Microsoft Outlook .ost file is given as:

C:\Users\username\AppData\Local\Microsoft\Outlook

Then, restarting the Outlook once would recreate a fresh .ost file without issues. It can resolve your issue if corrupt OST file is the problem.

Using manual methods to solve the issue of corrupted or orphaned OST files can be complex and time-consuming. Therefore, it is advisable to use the most efficient and secure third-party software named Kernel OST to PST Converter. It inaccessible OST file and allows to save it to the PST file format and other destinations. The tool is suitable for all users, including beginners, and it will get the work done in a hassle-free manner.

Microsoft Outlook allows you to create 1000 folders. If the number of subfolders exceeds the specified number, the folder will not expand. The limit is applicable to Microsoft Exchange accounts. There is a 500 folder limit for Outlook 2010, 2013, 2016, and 2019. In addition, no folder can contain more than 100,000 items. You might face performance issues in case these limits are exceeded. So, make sure you are within these prescribed limits.

Conclusion

The article has discussed valuable insights on the causes of the “Cannot expand the folder” error and relevant solutions to fix it. If the issue persists, then the reason could be corrupted or damaged OST files. In such cases, Kernel OST to PST converter is highly recommended. Its advanced algorithm provides an edge to the user to recover permanently deleted items. Check out the trial version to experience the credibility of the tool.