Are you having trouble starting Outlook 2016, Outlook 2013, or Outlook 2010, or receiving "Cannot start Microsoft Outlook. Cannot open the Outlook window" error messages? We can fix the problem for you, or you can use the troubleshooting steps we're providing below to help resolve these startup issues. 

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We can diagnose and fix several common Outlook issues for you. If our automated tool can't fix your issue, or if you'd like to fix it yourself, see the next section.

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Start Outlook in safe mode and disable add-ins

Sometimes add-ins can conflict with Outlook. Starting Outlook in safe mode, which starts Outlook without add-ins loaded, can tell you if an add-in is the problem.

Note: If you enabled an ABBYY FineReader add-in, an outdated version of the software might cause an Outlook startup error. For more information, see Office programs may crash with the FineReader add-in installed.

Start Outlook in safe mode

  1. Choose StartRun.

  2. Type Outlook /safe, and choose OK.

  3. In the Choose Profiles dialog box, accept the default setting of Outlook and choose OK.

    Accept default setting of Outlook in Choose Profile dialog box

  4. If prompted, enter your password and choose Accept.


  • How do you know you're working in safe mode? You'll see a label similar to the one below at the top of the screen.

    A label at the top of the window tells you the name of the person who owns the Inbox and identifies that Outlook is operating in safe mode

  • The Outlook Outlook icon overlaid with a caution symbol icon on your taskbar also alerts you the program isn't operating normally.

If Outlook does start in safe mode, then the problem is likely with one of your add-ins. You'll need to disable all of your add-ins before restarting Outlook.

Disable add-ins

  1. In the upper-left corner of Outlook, choose FileOptionsAdd-ins.

  2. At the bottom of the View and manage Office Add-ins, make sure the Manage box shows COM Add-ins, and then choose Go.

  3. As a precaution, when the COM Add-ins listing of your current add-ins opens, do one of the following:

    • Manually record the title of every selected add-in listed under Available Add-ins.


    • Take a screenshot of the property sheet and save the image to a location of your choice.

  4. After you've captured the titles of the selected add-ins, clear all selected check boxes, and then choose OK.

    Caution: Click a check box to clear it. Don't select an add-in and choose Remove. If you have administrator rights, you could actually delete the add-in. For this troubleshooting exercise, you want to disable, not delete, an add-in.

  5. Choose FileExit.


  1. Choose StartRun, and in the Open box, type Outlook.

    Note: If the program loads properly, it's likely that one of your add-ins is the source of the error and you need to identify which one. To determine which add-in is the problem, enable one add-in at a time.

  2. In the upper-left corner of Outlook, choose FileOptionsAdd-ins.

  3. Select the check box next to an add-in you want to re-enable, and then choose OK.

  4. Repeat all steps until you've re-enabled all of the original add-ins and revealed the source of the error.

    Important: Remember, if Outlook opens in safe mode, you've revealed the add-in you just enabled as a source of the error.

    • Restart Outlook again and disable the add-in you enabled that produced the problem, and then start Outlook.

    • Make sure you go through the restart-disable-restart process for every add-in that was originally enabled in Outlook. An error could be caused by more than one add-in.

Create a new Outlook profile

Your profile contains your Outlook settings. Occasionally, that profile can become corrupted. You can determine if it's corrupt by creating a new profile and changing which profile is used when Outlook starts.

  1. To open the Control Panel, do one of the following:

    • For Windows Vista or Windows 7, choose StartControl Panel.

    • For Windows 8 and Windows 10, choose Start, and then type Control Panel.

      Note: For Windows 10, in Control Panel, make sure the View by box in the upper-right corner is set to Category.

  2. Choose Mail.

  3. In the Mail Setup - Outlook dialog box, choose Show ProfilesAdd.

    Mail property sheet used to add or remove a profile for your Outlook account

  4. In the Profile Name box, type the name you want to use for your new profile.

    New Outlook mail profile being set up for kerimills

  5. On the Auto Account Setup page for the Add Account Wizard, under E-mail Account, fill in Your NameE-mail Address, and Password, and then choose Next.

    Use Auto Account Setup to add email account as part of newly created profile for Outlook

    Note: The Add Account Wizard automatically searches for your mail server settings.

  6. Choose Finish and you'll find the new profile name you added listed on the General tab in the Maildialog box.

  7. Under When starting Microsoft Outlook, use this profile, choose Prompt for a profile to be used, and then choose OK.

Use a different profile

  1. Restart Outlook

  2. In the drop-down list in the Choose Profile dialog box, choose the new profile name you created.

    Choose profile dialog box with the name of the new profile

  3. Choose OK.

    Note: If Outlook starts normally, then you've identified your Outlook profile as being corrupt and the source of your problem.