10 Ways to Fix “The Set of Folders Cannot be Opened”

While Outlook is a simple-to-use email client, there can be occasional glitches and errors when running it. One of these errors is the “The set of folders cannot be opened” error. This error usually occurs when Outlook cannot open its data file that stores all the information about the application.

Sometimes this can happen when another software is using that data file, causing Outlook to lose access temporarily. Other causes are corrupted files, faulty add-ins, errors with your profile on Outlook, or compatibility mode. Fortunately, there are simple ways to fix this error.

How to Fix “The set of folders cannot be opened”?

There are several easy ways to fix Outlook’s “The set of folders cannot be opened” error. Some of them are using safe mode, resetting the navigation pane, repairing the .pst data file, and more. But before trying these fixes, you can try restarting the app or your system. 

If this does not fix the error, you can try the mentioned fixes as detailed in this article. Let’s jump right to it.

Use Safe Mode to Disable Add-ins 

When you use Safe Mode to run Outlook, it will disable the add-ins temporarily. This can solve the error. Follow these steps to launch Outlook in Safe mode.

1. Press the Windows key + R.
2. Enter Outlook /safe in the text box.
   
3. Press Enter.
4. In the pop-up box that appears, select a profile, and press OK. 
   

If Outlook starts without a problem, it means you have faulty add-ins. You can check these add-ins individually and delete them from Outlook. You can follow these steps to do so.

1. Click on File > Options > Add-Ins.
2. Click the Go button at the bottom of the window.
   
3. Disable an Add-in by clicking on the box next to it.
4. Press the OK button.
   
5. Try to start Outlook again to see if it fixed the error.
6. If this fixes the issue, it means that you still have faulty add-ins. 
7. Repeat Steps 6 and 7 until you find the faulty add-in.

Reset the Navigation Pane on Outlook

Resetting the navigation pane on Outlook restores the default settings on Outlook. If you made changes in the app’s settings, it could cause temporary glitches and bring up this error. 

To reset the navigation pane, follow these steps. 

1. Press the Windows key + R to open Run.
2. Enter outlook.exe /resetnavpane into the textbox.
   
3. Press the OK button.

Repair the .pst Data File

The “The set of folders cannot be opened” error also occurs when your personal folder gets corrupted. This can happen due to glitches in the folder. To search for and fix these errors, you can use Microsoft’s ScanPST tool.

Follow these steps to do so.

1. Go to C:\Program Files (x86)\Microsoft Office\Office16 from File Explorer. Please note that the location might differ according to the version of your Outlook.
2. Run SCANPST.EXE.
3. Click on Browse.
4. Select the .pst file that you want to scan.
5. Click on Start.
   
6. If it shows you the errors, click on Repair.
   
7. Now start Outlook with the profile associated with this repaired data file. 

Repair Outlook Profile

An error in the .pst file can cause a corrupted Outlook profile. In that case, you can try repairing the profile instead of deleting it. Repairing can save your emails, contacts, and reminders. These steps will help you repair your profile.

1. Go to Microsoft Outlook.
2. Click on File.
3. Click on Account Settings to reveal a drop-down menu.
4. Click on Account Settings from the drop-down menu.
   
5. Go to the Email tab.
6. Click on the corrupted profile.
7. Press the Repair button.
   
8. Press the Finish button when you’re done.

Make a New User Profile

Sometimes an error or corruption in your user profile can also cause problems with Outlook. In that case, you’ll have to create a new profile. You should first delete the older profile and then create a new one. You can take these steps to do so.

1. Press the Windows key + R.
2. Write regedit in the text box.
   
3. Click on HKEY_CURRENT_USER.
4. Click on SOFTWARE.
5. Click on Microsoft > Office > 16.
   
6. Click on Outlook > Profiles.
   
7. Delete all the folders.
8. Restart Outlook.
9. Click on File.
10. Go to Account Settings > Manage Profiles.
    
11. Go to Show Profiles.
12. Press the Add button.
    
13. Enter your details and save.

Check for and Turn Off Compatibility Mode

If you use newer versions than Outlook 2007, Windows supports the software. So, running Outlook in compatibility mode is not supported by Windows. You can check if it is turned On in your system and then disable it.

You can follow these steps to do so.

1. Go to  C:\Program Files\Microsoft Office\Office 15\ or C:\Program Files (x86)\Microsoft Office\Office 15\ from File Explorer.
2. Look for the Outlook.exe file and right-click on it.
3. Click on Properties.
4. Go to the Compatibility tab.
5. Click on Run this program in compatibility mode for to unselect it.
   
6. Click the Apply button and then the OK button.

Note:  If you have older versions than Outlook 2007, you should change to a different email client since they are no longer supported on Windows. 

Delete XML Files

An XML file stores your data along with tags that tell the software what to do with that data. A corruption in this file can lead to this error. Deleting this file can solve this error. Follow these steps to do so.

1. Press the Windows key + R to open Run.
2. Type %appdata%\Microsoft\Outlook in the text box.
   
3. Click the OK button.
4. Select the Outlook.xml file and delete it.

Disable Cached Exchange Mode

Cached exchange mode connects Outlook with an exchange server. It keeps a copy of your Exchange mailbox stores on your hard drive. This file is a .ost file. When this mode is enabled, it will constantly check for and update your mail to the cached file. This can sometimes cause the set of folders cannot be opened error. So, to disable cached exchange mode, follow these steps.

1. Open Outlook.
2. Click on File > Account Settings.
3. Go to Account Settings.
   
4. Select a profile and click on Change.
5. Click on the box next to Use Cached Exchange Mode to uncheck it. 
   
6. Exit the window and restart Outlook.

Minimize the Size of Outlook’s Data

If you have a lot of emails in your Outlook, this error can occur. You can reduce Outlook’s data size by deleting or compressing some emails. Follow these easy steps to do so.

1. Open the Outlook app.
2. Go to File > Tools.
3. Go to Mailbox cleanup.
   
4. Remove everything from the Deleted Items folder if there’s anything there.
5. Go back to File > Account Settings.
6. Click on Account Settings > Data Files.
   
7. Select the files you want to compress.
8. Click on Settings.
9. Press the Compact Now button.
   
10. Restart Outlook to see if this fixed the issue.

Repair Office

Outlook has a .pst file that stores your messages and is stored on your computer. Sometimes corruption in this file can cause this error. When you repair Outlook, it can find and fix what caused this corruption. To repair your Outlook, follow these steps.

1. Go to Settings on your PC.
2. Click on Apps.
3. Go to Apps and Features.
   
4. Click on the three vertical dots next to Microsoft Office Professional 2021.
5. Select Modify.
6. Select Quick Repair and press the Repair button.
   
7. Click on Repair. 
8. After the repair process, restart Outlook to see if this fixed the problem.