Outlook not responding error or Outlook freezes when you open a file or send mail

When you open a file or send an email message in Microsoft Outlook 2010 or later versions, Outlook freezes. Or, you receive the following error message:

Outlook not responding

This problem occurs for one or more of the following reasons:

• You don't install the latest updates.
• Outlook is in use by another process.
• Outlook is loading external content, such as images in an email message.
• A previously installed add-in is interfering with Outlook.
• Your mailboxes are too large.
• Your AppData folder is redirected to a network location.
• You have to repair your Microsoft 365 programs.
• Outlook data files are corrupted or damaged.
• Your installed antivirus software is outdated, or it conflicts with Outlook.
• Your user profile has become corrupted.
• Another program conflicts with Outlook.

Many of these items can be automatically checked by the Classic Outlook Advanced Diagnostics troubleshooter.

To run the troubleshooter, follow these steps:

1. Select the following button to start the troubleshooter.

   Classic Outlook Advanced Diagnostics troubleshooter

   If you receive a pop-up window that displays "This site is trying to open Get Help.", select Open.

2. Follow the instructions in the Get Help app to run the troubleshooter.

After the troubleshooter finishes, it displays the results and provides additional information about how to resolve the issue.

To resolve this problem, make sure that your computer meets the Outlook 2016 system requirements, Outlook 2013 system requirements or Outlook 2010 system requirements.

The Office installation on your computer might not be up to date. The reason might be because Windows Update isn't configured on your computer to automatically download and install recommended updates. By installing important, recommended, and optional updates, you can often correct problems by replacing out-of-date files and fixing vulnerabilities. To install the latest updates, select the link for your version of Windows, and then follow the steps in the article:

• Install Windows updates in Windows 10
• Windows Update FAQ for Windows 8.1
• Install Windows updates in Windows 7
• Install Windows updates in Windows Vista
• Install Windows updates in Windows XP

Make sure that the latest updates for Outlook are installed. For more information, see How to install the latest applicable updates for Microsoft Outlook (US English only).

Performance may be decreased if you use the Outlook AutoArchive feature or sync to Outlook with a mobile device. These processes can use a large number of resources.

If Outlook is in use by another process, this information is displayed in the status bar at the bottom of the screen. If you try to perform other actions while Outlook is in use, Outlook may not respond. Let the task in process finish its job before you try another action.

To resolve this issue, use one of the following methods:

• Prevent Outlook to download external contents. To do so, go to File > Options > Trust Center > Automatic Download, select the following two options:
  • Don't download pictures or other content automatically in HTML e-mail option.
  • Warn me before downloading content when editing, forwarding, or replying e-mail.
• Avoid sending such an email with external source.

Although add-ins can enhance your user experience, they can occasionally interfere or conflict with Outlook. Try to start Outlook without any add-ins running.

1. Do the following, as appropriate for your operating system:
   • If you're running Windows 8, swipe in from the right edge of the screen, and then tap Search. (If you're using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then select Search.) Type Run in the search box, and then tap or select Run.
   • If you're running Windows 10, Windows 7 or Windows Vista, select Start.
   • If you're running Windows XP, select Start, and then select Run.
2. Type Outlook.exe /safe, and then select OK.
3. If the problem is resolved, select Options on the File menu, and then select Add-Ins.
4. Select COM Add-ins, and then select Go.
5. Clear all the check boxes in the list, and then select OK.
6. Restart Outlook.

If the problem doesn't occur after you restart Outlook, one of the add-ins is likely the cause of the problem. Restore the add-ins one at a time until the problem does occur to determine which add-in is causing the problem.

As your mailbox size increases, more resources are required to open each folder. If you have a large number of items in any single folder, you may experience performance issues during certain operations. For more information, see Outlook performance issues when there are too many items or folders in a cached mode .ost or .pst file.

We recommend that you move several items in your larger folders to separate folders, or that you archive those items by using the AutoArchive feature.

1. On the Folder tab, select New Folder in the New group.

2. In the Name box, enter a name for the folder.

3. In the Select where to place the folder list, select the location for the new folder.

   Note

   The new folder becomes a subfolder of the folder you select.

4. Select OK.

To manage your mailbox by reducing the size of the Outlook data file, see Reduce the size of Outlook Data Files (.pst and .ost).

To manage your mailbox by using the AutoArchive feature, see AutoArchive settings explained.

Outlook stores certain data, such as email signatures and the spelling checker dictionary, in the AppData folder. If the network is performing slowly, Outlook must wait for read and write operations to the AppData directory to finish.

1. Exit Outlook.

2. Start Registry Editor. To do so, use one of the following procedures, as appropriate for your version of Windows:

   • Windows 10 or Windows 8: Press Windows Key+R to open a Run dialog box. Type regedit.exe and then press OK.
   • Windows 7: Select Start, type regedit.exe in the search box, and then press Enter.

3. In Registry Editor, locate and then select the following subkey:

   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders

4. Locate and then double-click the AppData value.

5. In the Value data box, type the following path, and then select OK:
   %USERPROFILE%\AppData\Roaming

   

6. Exit Registry Editor.

You can automatically repair your Office program files to resolve such problems as Outlook freezing or not responding.

1. Exit any Microsoft Office programs that are running.
2. Open Control Panel, and then open Programs and Features (if you're running Windows 10, Windows 8, or Windows 7).
3. In the list of installed programs, right-click Microsoft Office 2016, Microsoft Office 2013, or Microsoft Office 2010, and then select Repair.

When you install Outlook, an Inbox repair tool (scanpst.exe) is also installed on your PC. The Inbox repair tool can resolve problems by scanning your Outlook data files, and repairing errors. To use the Inbox repair tool, exit Outlook, and then follow the steps in Repair Outlook Data Files (.pst and .ost).

If your antivirus software isn't up-to-date, Outlook may not function correctly.

To keep up with new viruses as they're created, antivirus software vendors periodically provide updates that you can download from the Internet. Download the latest updates by visiting your antivirus software vendor's website.

For a list of antivirus software vendors, see Consumer antivirus software providers for Windows.

If your antivirus software includes integration with Outlook, you may experience performance issues. You can disable all Outlook integration within the antivirus software. Or, you can disable any antivirus software add-ins that are installed in Outlook.

You may have to contact your antivirus software vendor to determine how to configure the software to exclude any integration with Outlook or to exclude scanning in Outlook.

To create a user profile, follow these steps:

1. In Control Panel, select Programs, select User Accounts, and then select Mail to open Mail items.

2. Select Show Profiles.

3. Select the profile that you want to remove, and then select Remove.

4. Select Add.

5. In the Profile Name dialog box, type a name for the profile.

6. Specify the user name, the primary SMTP address, and the password. Then, select Next.

7. You may receive the following prompt:
   Allow this website to configure <alias@domain server> settings?

   In this prompt, select the Don't ask me about this again checkbox, and then select Allow.

When you start Windows normally, several applications and services start automatically and then run in the background. These applications and services can interfere with Outlook. A Selective Startup or "clean boot" process can help you identify problems that are caused by application conflicts.

If you use the Selective Startup option in System Configuration, you can turn services and startup programs on or off individually to check whether the problem occurs the next time that you start your computer. In System Configuration, if you select a check box, the related service or startup program runs when you restart the computer. If the check box is cleared, the service or startup program doesn't run when you restart the computer.

Follow this procedure to use the process of elimination to identify the problem in Windows 10, Windows 8, Windows 7, or Windows Vista.

1. In Control Panel, select System and Security, select Administrative Tools, and then double-click System Configuration.

   Note

   If you're prompted for an administrator password or for confirmation, type the password or provide confirmation.

2. Select the General tab, select Selective startup, and then clear the Load system services and the Load startup items check boxes.

3. Select the Load system services check box, select OK, and then select Restart.

4. If the problem reoccurs after you restart the computer, do one or both of the following tasks, as necessary.

   To determine which system service is causing the problem

   1. In System Configuration, select the Services tab, select Disable all, select the check box for the first service that is listed, and then restart the computer.

      Note

      If the problem doesn't reoccur, then you can eliminate the first service as the cause of the problem.

   2. With the first service selected, select the second service check box, and then restart the computer.

   3. Repeat this process until you reproduce the problem.

      Note

      If you can't reproduce the problem, you can eliminate system services as the cause of the problem.

   To determine which startup item is causing the problem

   1. In System Configuration, select the General tab, and then select the Load startup items check box.

   2. Select the Startup tab, select Disable all, select the check box for the first startup item that is listed, and then restart the computer.

      Note

      If the problem doesn't reoccur, you can eliminate the first startup item as the cause of the problem.

   3. While the first startup item is selected, select the second startup item check box, and then restart the computer. Repeat this process until you reproduce the problem.

Your user profile is a collection of settings that let you customize the computer appearance and performance. It contains settings for desktop backgrounds, screen savers, sound settings, and other features. User profiles help make sure that your personal preferences are used when you log on to Windows.

To determine whether this problem is caused by a corrupted user profile, create a user profile to see whether the problem still occurs when you use the new profile.

To create a user profile, you must first create a user account. When the new account is created, a profile is also created.

1. Swipe in from the right edge of the screen, and then tap Search. (If you're using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then select Search.) Type Command Prompt in the search box, right-click Command Prompt, and then select Run as administrator.

   Note

   If you're prompted for an administrator password or for confirmation, type the password or provide confirmation.

2. Type net user UsernamePassword /add, and then press Enter.

1. Sign in as a user other than the user that you just created or the user that you want to copy files from.

2. In Control Panel, select Appearance and Personalization, and then select Folder Options.

3. Select the View tab, and then select Show hidden files, folders, and drives.

4. Clear the Hide protected operating system files check box, select Yes to confirm, and then select OK.

5. Open File Explorer. To do this, Swipe in from the right edge of the screen, and then tap Search. (If you're using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then select Search.) Enter File Explorer in the search box, tap or select Apps, and then tap or select File Explorer. Type Command Prompt in the search box, right-click Command Prompt, and then select Run as administrator.

6. Locate the C:\Users\Old_Username folder, in which C is the drive that Windows is installed on, and Old_Username is the name of the profile that you want to copy files from.

7. Select all the files and folders in this folder, except the following files:

   • Ntuser.dat
   • Ntuser.dat.log
   • Ntuser.ini

8. On the Edit menu, select Copy.

   Note

   If you don't see the Edit menu, press Alt.

9. Locate the C:\Users\New_Username folder, in which C is the drive that Windows is installed on, and New_Username is the name of the user profile that you created earlier in this method.

10. On the Edit menu, select Paste.

11. Sign out, and then sign in as the new user.

If the information in this article does not help resolve your problem in Outlook 2016, Outlook 2013 or Outlook 2010, see the following resources for more information:

• Perform a search to find more online articles about this specific error
• Visit the Microsoft Community online to post your question about this error
• Find the appropriate phone number to contact Microsoft Support

• Fix a corrupted user profile in Window 7
• Create a user account in Windows