Fix 'The Set of Folders Cannot be Opened' Error in Outlook 2016

Updated on November 09, 2023 by Nasir Khan

Like two sides of a coin, Outlook also has two sides; one offers numerous modern-day advancements while another has errors and issues. Due to ease of use and interaction with Microsoft Office and other Microsoft services, businesses and individuals extensively use MS Outlook as an email client. It also supports Exchange, which is helpful for business modern-day email correspondence. However, Outlook users frequently encounter several difficulties when using it. Among several issues, the most common one is "The set of folders cannot be opened." This problem frequently prevents users from viewing their Outlook emails and texts.

In this article, we will go through the error and discuss some effective methods to resolve it so that you can avoid future related issues. Also, a complete guide for the users facing this issue will also be included in this write-up.

Popup Error in Outlook 'The Set of Folders Cannot be Opened'

What Leads to "The Set of Folders Cannot Be Opened" Error in Outlook 2016?

There are a lot of reasons that are responsible for this issue. We can’t directly figure out a single cause for this. However, it is likely caused by Outlook data file corruption or a damaged.xml file containing your Outlook username. Below are a few other reasons that can cause the “The set of Folders cannot be opened in Outlook” error.

Corrupted Outlook Profile: A corrupted Outlook profile is one of the primary culprits for this error. The profile stores your email settings, account information, and other configuration details. When it becomes corrupted, Outlook may fail to open.

Corrupted Data Files (PST/OST): Outlook relies on Personal Storage Table (PST) and Offline Storage Table (OST) files to store your email data. If these files become corrupted for various reasons, including abrupt system shutdowns or disk errors, it can lead to the error.

Third-Party Add-Ins: Some third-party add-ins or extensions for Outlook can be incompatible or malfunction, causing conflicts that prevent Outlook from opening correctly.

Antivirus or Security Software Interference: Overly aggressive antivirus or security software can sometimes interfere with Outlook's normal functioning, leading to this error.

Windows Updates: Occasionally, Windows updates can introduce changes that impact Outlook's functionality, causing it to fail to open.

Disk Errors or Disk Space Issues: Physical disk issues or insufficient disk space on your computer can prevent Outlook from accessing necessary data files.

Exchange Server Issues: For users connected to Microsoft Exchange servers, server-related problems, such as server downtime or misconfigurations, can cause this error.

Each of these potential causes requires specific troubleshooting steps to identify and resolve. In the following sections, we'll explore solutions to address each of these issues to help you fix the "The Set of Folders Cannot Be Opened" error in Outlook 2016.

13 Verified Solutions to Fix 'The Set of Folders Cannot Be Opened' Error in Outlook

Before beginning the approach, backup your Outlook data files and ensure your device is operating as an administrator. Additionally, you must shut down Outlook because the solutions may not function if Outlook is open in the background. Read the solutions step by step as follows:

1) Update the MS Outlook Program

It is necessary to keep your Outlook application up-to-date. You need to check for updates. If you need to perform an update, do it at once by following the steps below.

1. Choose Office Account from the File menu.
2. Next, navigate to Office Update.
3. Select Update Settings.
4. Select the Update Now button to update the Outlook email program.

2) Run Your MS Outlook in Safe Mode

1. Running Outlook in safe mode is among the simplest ways to resolve this problem. MS Outlook launches in safe mode without activating any add-ins. To run Outlook in safe mode, perform the following steps:
2. By entering "Window+R," you may launch the Run command.
3. Enter "Outlook/safe" and click OK.
4. When the "Choose Profile" dialog box appears, click "OK." In this section, you can get the option of entering your password.
5. As Outlook launches in safe mode, the add-ins have an issue. Inspect the status bar at its highest point to see if Outlook is in Safe Mode.

If you ensure that Outlook is working in safe mode, the error is caused by faulty add-ins. You need to turn off the suspicious add-ins and restart Outlook.

3) Reinstall Office

If you don’t know how to repair the Office installation, then read the steps as follows:

1. From the Windows control panel, select the programs and features option.
2. Next, under Programs and Features, pick Office from the drop-down menu.
3. Choose Change to start the Quick Repair procedure.
4. Use the Online Repair tool if the issue still appears when you begin Outlook.

4) Exclude XML files from the Outlook Directory

We know that XML files save Outlook user’s profiles and settings that are customized. Any issue with the XML may also lead to errors in Outlook and thus result in errors. So, if we face the “the set of folders can’t be opened error, then removing these .xml files is a wise decision. Follow the steps to remove these files:

1. Concurrently press the “Windows” with “R” and write “Appdata”>> Enter.
2. Or Follow the command: C:\Users\PCName\AppData\Local\Microsoft\Outlook
3. This command or first step will take you to the XML file present.
4. Now, simply delete these outlook.xml files and check if the issue is resolved by restarting Outlook.

5) Remove Your Outlook Account from the Mail App

Adding your Outlook account to Mail App despite adding them on the Outlook email client also cause some synchronization issue that also causes an error, especially when opening a set of folder. So, it is better to remove your account from the Mail App. Follow the below-given steps to remove:

1. Open the Windows Mail app from the taskbar or by searching the list of installed applications.
2. Now click on the gear icon of settings. Find the icon as per the screenshot given below.
3. Here, click on the Manage accounts and select the account that you want to delete.
4. Click on the option “Delete account from this device.”
5. Now, confirm by clicking on the Delete button.

6) Upgrade from 32-bit to 64-bit

It has been noticed that errors like “The set of folders cannot be opened” encounters mostly in the 32-bit version of Office. So, if you have 32-bit, then you can try to resolve this issue by upgrading it to 64-bit. If you are already using 64-bit, then you can reinstall it to resolve the error if it is caused by it.

7) You Can Also Try Resetting the Navigation Pane

In Outlook’s GUI, the left pane where we get all the folders is called the navigation pane. Experts have noticed that resetting the navigation pane also resolves the “The set of folders cannot be opened” error. Follow the steps to reset the navigation pane:

1. First, close the Outlook application.
2. Keep the Ctrl key pressed and open Outlook.
3. To launch Outlook, double-click on the Outlook icon; if the desktop icon is not available, then open it from the list of installed applications.
4. Or you can simply press “Windows+ R” and enter the given command to reach:“outlook.exe /resetnavpane.”
5. By this, you can easily reset the navigate pane and also resolve the issue of folders not opening.

8) Create a New Outlook Profile

All Outlook users are well versed in the Outlook profile’s importance as it keeps all settings related to the Outlook account. If updating the Outlook program did not resolve the issue "the set of folders cannot be opened," you must rebuild the Microsoft Outlook profile. This strategy has assisted many people in resolving the problem. So, if any issue persists with the Outlook profile, then it may lead to the 'The set of folders cannot be opened' error. So, we should create a new Outlook profile to check if the issue is caused by this or not. If yes, then it will get resolved. Follow the steps to create a new Outlook profile:

1. Go to the Control Panel and select the Mail (Microsoft Outlook 2016).
2. Now click on the Shows Profile >> Add button to add a new profile.
3. Give a name to the new profile and click OK.
4. You will be prompted to the “Auto Account Setup” window, where you have to provide the email account details and click Next.
5. A new Outlook Profile has been created. Use the option 'Always use this profile' to make it a default Outlook profile. Click Ok.
6. Restart the Outlook using the new Outlook Profile and check if the issue has been gone or persists. If the error has been resolved, then it indicates that there was some problem with the old Outlook profile.

9) Use Microsoft Support and Recovery Assistant

To provide an instant solution to some common issues faced by Microsoft users, Microsoft has offered MSRA (Microsoft Support and Recovery Assistant). For the 'The set of folders cannot be opened' error, you can also use this diagnostic tool by Microsoft. Simply search on the search engine for MSRA, and you will get the Microsoft page with a download link.

10) Use App Password for Two-Step Authentication

1. To use the app password, first enable the two-step verification.
2. To enable two-step verification, open the Microsoft account security settings and follow the on-screen instructions.
3. Now, you need to generate an app password. Use the option 'Create a new app password' in Microsoft account security settings.
4. Open the Outlook File tab >> Account settings.
5. Enter the created app password and save the changes in Outlook.
6. Finally, Restart the Outlook and see the changes.

11) Run Outlook Mailbox Cleanup

To deal with “The set of folders cannot be opened,” you must try the mailbox cleanup facility by Outlook. Follow the steps:

1. Open Outlook >> File.
2. Click on the Info >> Tools >> Mailbox Cleanup…
3. Use the clean-up options as per the need and check if the problem is resolved.

12) Repair Outlook PST Files

It can happen that your Outlook PST files have been corrupted or damaged. As Outlook uses pst-formatted files to save data, corruption of the PST files can create the following error. However, Microsoft has provided an in-built feature in Outlook (the ScanPST Tool) to repair damaged PST files. Read the steps as follows to use the facility.

1. If you are using Outlook 2016, close Outlook if it is running in the background. Next, navigate to this location: “C:\Program Files (x86)\Microsoft Office\root\Office16”.
2. Find and run SCANPST.EXE.
3. Choose the relevant Outlook PST file by clicking the Browse button.
4. Pick Repair after clicking the Start button.

These are the native methods to repair the set of Outlook folder cannot be opened error. However, apart from these methods, you can create a new PST file and upload it to your Outlook profile, which can also fix this error. Also, we should keep in mind that these manual solutions are not a one-stop solution. There are some limitations and drawbacks associated with them, Let’s know:

Scanpst.exe doesn’t work for the severely corrupted PST files. They are only suitable for minute corruption issues.
There is also a limitation for the Outlook PST size.
In many scenarios, the Scanpst.exe utility fails to read the PST files. Also, it can’t work on the password-protected PST files.
With other manual methods, you are just giving a try; no guarantee of successful resolution of the error. Also, you should be technically sound to execute these manual ways without data loss.

To deal with this issue professionally, we suggest having the Regain Outlook PST Recovery Tool in your software bucket. It is one of the most trusted and praised software by Outlook users to manage their PST files effectively. The software is compatible with all Outlook versions and supports both ANSI and UNICODE-formatted PST files. Some of this tool’s features are given below:

Free Download100% Secure Buy Nowinstant delivery

Why Regain PST repair tool is a must-have solution for Outlook users?

The software allows you to repair corrupt PST files of any Outlook version without installing Outlook in your system.
You can migrate Outlook PST files into Office 365, Live Exchange, G Suite, and several other popular cloud-based servers.
Regain PST Repair tool allows converting PST files into different file formats such as EML, MSG, HTML, vCard, etc.
You don’t need technical expertise to manage your PST files, as you get all the options in your dashboard. Using this software is the same as using Android apps, so there is no need for any extra technical knowledge.
It is the most pocket-friendly PST repair and management software in the market. You can also have the free version of the software to evaluate it with your needs and Outlook environments.

Fix Set of Folders Cannot Be Opened Outlook error Using Regain Software

This tool is developed by keeping users at the centre of the development process hence very user-friendly. Just follow the below-given steps to use it:

Install and launch the software. You will get a welcome screen.
Now simply add the corrupted PST files by browsing them. Click on the open.
The software will now read the PST files and show the preview after recovery.
Now you can have the preview of the data present within the PST file.
Here, you have to provide the destination path to save the PST file. Also, you have to select the file format in which you want to save the data. There are multiple options. For now, we will choose PST file format as we need data in Outlook. Using split PST, you can also set the size for the resultant PST files.
Click on Convert Now and the process of saving will start. You will get a message as the process completes.

Wrapping up:

In this comprehensive guide, we've explored the vexing "The Set of Folders Cannot Be Opened" error in Outlook 2016, a frustrating issue that has been the bane of many Outlook users. From the causes of this error to detailed solutions like the Regain Outlook PST repair tool, we've covered it all to help you resolve this problem and regain control of your Outlook experience. Following the steps outlined in this guide, you can troubleshoot and fix the "The Set of Folders Cannot Be Opened" error in Outlook 2016, ensuring that your email communication and productivity are no longer disrupted.

Frequently Asked Questions:

Q1: What is the significance of Outlook profiles, and why do they sometimes get corrupted?

Ans: Outlook profiles store your email settings, account information, and configuration details. They can become corrupted for various reasons, such as software conflicts, abrupt system shutdowns, or disk errors. When a profile becomes corrupted, it can lead to errors like "The Set of Folders Cannot Be Opened."

Q2: Can third-party add-ins cause issues with Outlook?

Ans: Yes, third-party add-ins or extensions can indeed cause problems in Outlook. They can be incompatible, malfunction, or conflict with other add-ins or Outlook's core functionality, leading to errors like "The Set of Folders Cannot Be Opened."

Q3: How can I prevent the "The Set of Folders Cannot Be Opened" error in Outlook?

Ans: To prevent this error, consider keeping your Outlook application up-to-date, regularly backing up your Outlook data files (PST/OST), and being cautious when installing third-party add-ins. Additionally, ensure your computer has sufficient disk space, and configure your antivirus or security software not to interfere with Outlook.

Q4: How can I ensure my Outlook PST files remain healthy and error-free?

Ans: To maintain healthy PST files, it's important to back up your data regularly, avoid abrupt system shutdowns, and keep your Outlook application and operating system up-to-date. Using reliable antivirus and security software can help protect your email data from corruption.

Q5: Does the "The Set of Folders Cannot Be Opened" error only affect Outlook 2016?

Ans: No, this error can affect various versions of Outlook, not just Outlook 2016. The solutions provided in the guide can be adapted for different Outlook versions, but the specific steps may vary slightly depending on your version.