Microsoft Outlook is the No. 1 software for managing emails. It allows you to send and receive electronic messages manage your schedule and your tasks. Outlook is pretty easy to get started with.
Microsoft Outlook users have encountered some errors in the last ten years. As of Outlook 2010, future versions of users, including Office 365, will continue to report. Users will see a popup that says outlook the set of folders cannot be opened. This happens when you expand a shared folder or a shared folder in the other mailbox.
It is not clear how this bug will continue, but Office 2019 users appear to be in better shape. Consider upgrading to this version.
On Outlook, you can create folders. A good way to give meaning to the emails received! Just right-click on “Inbox” or another item in the left column. You can then create a folder and store it wherever you want.
Folder Restrictions
Microsoft Outlook contains up to 1,000 folders. If there are more subfolders than specified, the folders do not expand. This limit applies to Microsoft Exchange accounts. This maximum size is 500 for Outlook 2010, 2013, 2016, and 2019. In addition, the number of items per directory does not exceed 100,000. Microsoft states that border violations can lead to performance issues.
Disable extensions
Have you installed the Add-in for your Microsoft Outlook account? One or more add-ons can cause conflicts and cause an error in not expanding the folder in Outlook. Open Outlook in safe mode and get rid of all add-on problems. You can also disable all plugins without going into safe mode. If the error disappears, re-enable each plugin simultaneously to determine the cause of the error.
Disable cache mode
Does this happen with Exchange accounts or shared mailboxes? In this case, disabling cache mode will help resolve the “Could not extract folder” error in Outlook.
- Click the File Options menu.
- Click “Account Settings” and select “Account Settings” from the drop-down list
- A list of all email accounts is displayed. Double-click the email ID that shows the “Could not extract folder” error.
- Now clear the Use cached exchange mode check box to save your settings.
Turn it off, save settings, close Outlook, restart and try again. The cache file may be the cause of the folder’s unusual behavior. When queuing is disabled, Outlook syncs folders and emails again and downloads them again.
Repair Outlook from the app
If you have this version or version of the Microsoft Office suite installed, look for a standalone Outlook app. Select it and click the Edit button at the top.
A popup with two options appears. Offline repair fixes the most common errors. Try it first. If that doesn’t work, try fixing it online.
Create a new Outlook profile
We recommend that you follow step 4 above before proceeding to create a new profile. Rename folders that cannot be expanded in Outlook. Click on the folder and select the Rename option. Make backups as needed.
Repair PST and OST files
If you select Cached Exchange Mode, Microsoft Outlook will create an OST file when configured on Exchange Server. When you are offline, this OST file gives you access to Outlook and changes such as writing, deleting, and editing emails. When you log in and connect to an Exchange server, these changes are automatically synced to your Exchange mailbox.
However, you may encounter Outlook synchronization issues due to poor network connection, Exchange server crashes, incorrect Outlook profile settings, or OST corruption. When you try to synchronize an offline directory (.ost) file with an Exchange server, you may receive an error message that is similar to the following:
Microsoft Outlook could not be started. The Outlook window could not be opened. Not all folders can be opened. The file c: \ Users \ AppData \ Local \ Microsoft \ Outlook \ is not an Outlook data file (OST).
If you use an IMAP or POP account, your Outlook email account data is saved in a . PST file. If you use an Office 365 or Exchange account, it will be saved.OST file. Select a method for the email account that gives the “Failed to expand folder” error in Outlook.
Repair of OST files
Open Control Panel and go to User Accounts> Email> View Profile. Select the offensive profile and click Properties below. Then select the data file in the next popup window.