How to Resolve “Outlook Cannot Expand the Folder” Error?

Summary: Microsoft Outlook users have encountered a critical error for the past decade. It commenced with Outlook 2010 and users of later variants continue to report it, including Office 365. Users see a pop-up error in MS Outlook saying ‘Cannot expand the folder’ or “Outlook cannot expand the folder”. This occurs while expanding a shared folder or folder in a second mailbox.

So if you have also faced or facing issues like you “cannot expand the folder Outlook” and do not get a plan out of this, then reading this technical essay is a must for you.

Here we are proceeding to explain the best methods to resolve this error and let you access the folder again to continue on with your work.

The error message that appears while trying to access the account mailbox folder is like this

error message

Why & How does the “Outlook Cannot expand the folder” error occur?

The above error is well-known in MS Outlook 2010, 2013, and later versions; it happens when the Outlook user tries to expand the shared folder, address book, public folder, or another secondary mailbox from the interface. Rather of expanding the particular folder, the error saying:

“Cannot expand the folder in Outlook.”


“Outlook can not expand the folder. Outlook cannot access the specified folder.”

Now before moving to a solution let us know what causes can be considered for the appearance of this error.

Major reasons that can be accountable for the “Cannot Expand the Folder” error In Outlook

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

Top Manual Methods to Resolve “Outlook Cannot expand the folder” Error

In this section of the blog, you are going to learn the right solution for the “ Microsoft outlook cannot expand the folder” error. Now that you know why MS Outlook is throwing this error, let’s take a step forward and figure out how to apply the needed fixes and run the application without any hitch.

Try the mentioned manual solutions one by one to fix this Outlook Error:

1# Make the folder “Visible”

Before performing this solution ensure that there are extra subfolders than the limit, i.e., maximum 500. Then confirm if the authority for the .ost folder view is allotted or not.

  • Firstly open the Outlook application interface, right-click the folder that is not responding, and click on the Properties option.
  • Secondly, check the Permissions tab and make sure that “Folder Visible” permission is assigned.
  • If not assigned then click on the Edit option and assign the same. Hit OK to save the settings.
  • Naively, you are able to solve the issue.

2# Disable the Cached Mode

You can also face a struggle in expanding the individual folder due to synchronization issues when the Exchange cached mode is on. Therefore it is advised to disable the cached Exchange mode in Microsoft Outlook in such a situation. Learn from the below steps.

  • On Outlook interface -> File -> Account Settings -> Account Settings.
account setting
  • Next, in the Account Settings page, under the Email section, double click on the account causing the issue. And, under the Offline Settings section, in the Change Account page. unselect the Use Cached Exchange Mode option and hit  Next to complete this process and save this setting.
use cached exchange mode option
  • Again try to restart Outlook and try expanding the folder.

3# Disable Microsoft Outlook add-ins feature

Execute this solution and try disabling the Outlook add-ins using the following method because many times it happens that conflicts with the third-party add-ins can affect the synchronization of the mailbox and functioning of the application. 

  • Opnr Outlook interface> Click File > Info > Options.
click option
  • Now on the Outlook Options page, tick Add-ins. From the right panel choose the option against Manage > COM Add-ins.
click go
  • After that unselect the Add-ins and click on OK.
hit ok
  • Again try to restart the Outlook application and then try expanding the folder again.

4# Repair the Outlook application

The Outlook application may also get corrupt and shows errors due to any bugs, errors, or other issues. Just follow this solution as an opinion, by doing an online repair on your Microsoft Office application suite. Just make sure you have a high network speed to perform this repair. Follow the below process to repair Outlook.

  • Open Control Panel > Programs and Features.
  • Find the Microsoft Office program and right-click on it. Pick the Change option from the drop-down list.
  • Next click Yes to continue.
  • Now select the Quick Repair option and agree on Repair.
  • Follow the next step to perform the repair.
  • After that try accessing the folder from the Outlook application once the repair is accomplished.

5# Create a new Outlook profile

A corrupt Outlook profile can be another reason that could be a cause for this error. So Outlook users can anytime create a new Outlook profile and set it as the default one.

Perform the following steps to create a new Outlook profile.

  • Click Control Panel and hit the Mail option.
  • Now click on the Show Profiles option from the new dialogue box.
show profile
  • Click Add to add a new profile and give a name for the new Outlook profile and tick OK.
click add
  • Next, set this profile to your account by choosing the option saying “Always use this profile” and then select the account from the drop-down list. Click on OK.
click ok
  • Now restart MS Outlook with this new profile and check if the problem is solved.

6#Repair the Outlook Database File

The corrupt .ost file can also be a reason for the error, so repairing it can also solve Outlook error but here the advantage that you can anytime regenerate the .ost of your configured Exchange Server account. Thereafter you just need to open the .ost file location from the Account Settings in Outlook and then remove the problematic .ost file from there using the Delete option simply.


Below is the default location of the default Microsoft Outlook .ost file :


After that again restart the Outlook once you recreate a fresh .ost file without issues. Doing this can fix your error “ Outlook cannot expand the folder in Outlook” if corrupt .ost is the problem. Also, you can fix Outlook Error 0x800ccc0f with inbox repair tool.

For users who have damaged or inaccessible.ost files, we advise the most effective and reliable SysInfoTools OST to PST Converter Software, which quickly recovers data from the corrupt, damaged, or orphaned offline .ost file and allows to save it to the PST file format and more further formats. Get complete awareness about the tool by visiting its authentic website.

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