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

Cause

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

• You have not installed 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 Office programs.
• Outlook data files have become 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• Your installed antivirus software is outdated, or it conflicts with Outlook.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.

Resolution

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

Step 1 – Install the latest updates
The Office installation on your computer might not be up to date. This might be because Windows Update is not 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 By installing important, recommended, and optional updates, you can often correct problems by replacing out-of-date files and fixing vulnerabilities.

Step 2 – Make sure that Outlook is not in use by another process
Performance may be decreased if you use the Outlook AutoArchive feature or sync to Outlook with a mobile device. This is because 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.

Step 3 – Check the problem caused by external content
To resolve this issue, use one of the following methods:

Prevent Outlook to download external contents. To do this, 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.

Step 4 – Investigate possible add-in issues
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.

How to start Outlook without add-ins

• Do the following, as appropriate for your operating system:
• If you are running Windows 8, swipe in from the right edge of the screen, and then tap Search. (If you are 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 are running Windows 10, Windows 7 or Windows Vista, select Start.
• If you are running Windows XP, select Start, and then select Run.
• Type Outlook.exe /safe, and then select OK.
• If the problem is resolved, select Options on the File menu, and then select Add-Ins. Select COM Add-ins, and then select Go.
• Clear all the check boxes in the list, and then select OK.

Restart Outlook.
If the problem does not 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.

Step 5 – Check whether your mailbox is too large
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.

How to create a folder

• On the Folder tab, select New Folder in the New group.
• In the Name box, enter a name for the folder.
• In the Select where to place the folder list, select the location for the new folder.
• The new folder will become a subfolder of the folder you select.
• Select OK.

Step 6 – Check whether your AppData folder is being redirected to a network location
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.

How to disable redirection of the AppData directory
Exit Outlook.

Start Registry Editor. To do this, 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.
In Registry Editor, locate and then select the following subkey:

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

Locate and then double-click the AppData value.

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

Exit Registry Editor.

Step 7 – Repair Office programs
You can automatically repair your Office program files to resolve such problems as Outlook freezing or not responding.

How to automatically repair Office

• Exit any Microsoft Office programs that are running.
• Open Control Panel, and then open the Add or Remove Programs item (if you are running Windows XP) or Programs and Features (if you are running Windows 10, Windows 8, Windows 7, or Windows Vista).
• In the list of installed programs, right-click Microsoft Office 2016, Microsoft Office 2013 or Microsoft Office 2010, and then select Repair.

Step 8 – Repair Outlook data files
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).

Step 9 – Check whether antivirus software is up-to-date or conflicts with Outlook
If your antivirus software is not up-to-date, Outlook may not function correctly.

How to check whether antivirus software is up to date
To keep up with new viruses as they are 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.

How to check whether antivirus software conflicts with Outlook
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.

Step 10 – Create a user profile in Outlook
To create a user profile, follow these steps:

• In Control Panel, select Programs, select User Accounts, and then select Mail to open Mail items.
• Select Show Profiles.
• Select the profile that you want to remove, and then select Remove.
• Select Add.
• In the Profile Name dialog box, type a name for the profile.
• Specify the user name, the primary SMTP address, and the password. Then, select Next.
• 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.

Step 11 – Perform a Selective Startup (advanced users)
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 does not 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.

How to do a Selective startup

• In Control Panel, select System and Security, select Administrative Tools, and then double- click System Configuration.
• Select the General tab, select Selective startup, and then clear the Load system services and the Load startup items check boxes.
• Select the Load system services check box, select OK, and then select Restart.
• 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
• 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.
• With the first service selected, select the second service check box, and then restart the computer.
• Repeat this process until you reproduce the problem.
• To determine which startup item is causing the problem
• In System Configuration, select the General tab, and then select the Load startup items check box.
• Select the Startup tab, select Disable all, select the check box for the first startup item that is listed, and then restart the computer.
• 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.

Step 12 – Create a Windows user profile (advanced users)
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.