Outlook won’t start – what now?

Outlook is a useful e-mail program with which you can avoid logging into the website of your provider to check your inbox. Nevertheless, even this popular element of Microsoft Office sometimes falls short – especially when you cannot open the Outlook window at all.

This is especially frustrating when you are waiting for an important e-mail. Usually, outdated software or a profile in need of repair are the reasons why you cannot start Microsoft Outlook. If a specific error code is displayed, the problem can be quickly identified, but many users do not know how to proceed in such specific instances. If the source of the problem is unknown, then you’re up a creek without a paddle. In the following sections, you will find out solutions for typical errors and what to do when faced with more unfamiliar ones.

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Outlook will not open and displays an error code

The error message, “Cannot start Microsoft Outlook. Cannot open the Outlook Window,” appears relatively often and is usually due to one of these causes:

  • Navigation Pane issue
  • Defective add-in
  • Outlook profile in need of repair

Multiple possible solutions, which will be introduced in the following sections, apply to the current Outlook 2016 as well as to the 2013 and 2010 versions. The only place there may be isolated variations are with the different versions’ menu navigation and input windows.

Reset the navigation pane with the command outlook.exe/resetnavpane

Outlook’s navigation pane is usually found on the left edge of the application window. It includes the folder list as well as the menu items, “E-Mail,” “Calendar,” “Contacts,” “Tasks,” and “Notes.” This area can be adjusted according to your preferences, but such individualizations sometimes leads to errors severe enough that Outlook will not open.

The solution involves reverting the navigation pane to its default setting:

  • Depending on your operating system: click “Run” in the Start Menu, or simultaneously press the Windows key and “R” to open the “Run” dialog box
  • Type in the command outlook.exe /resetnavpane (note the blank space) into the text field and confirm it by pressing “OK”
  • Start Outlook

The resetnavpane command stands for “reset navigation panel.”

Identify defective add-ins in safe mode

If this quick solution does not work, the next suspected culprits are the add-ins that are integrated into Outlook. These can either be defective or simply outdated and prevent Outlook from starting as usual.


Outdated versions of add-ins can cause an issue when trying to start Outlook.

Diagnosing this problem only works in the safe mode:

  • Open the “Run” dialog box (as previously described), type in the command outlook.exe /safe (note the space here, too), and confirm with “OK”
  • If the “Choose Profile” dialog box opens, choose the standard settings and click “OK” once more
  • Outlook will now start in safe mode without add-ins

Once the launch in safe mode is complete, you will have narrowed in on the issue: one or several of the add-ins may be preventing Outlook from starting normally. To find out which it is, complete the following steps:

  • In the top left of your Outlook window, click on the “File” tab and then on “Options”
  • On the left side of the window, choose “Add-Ins” and click “Go” toward the bottom of the add-ins window
  • Deactivate all add-ins (a completely harmless action), by unchecking their corresponding boxes in the list that opens
  • Restart Outlook normally (in other words, without safe mode)

If the restart was successful, this further indicates that one or more defective add-ins are at fault. Now, you should find out which ones are the culprits by process of elimination:

  • Activate each of the add-ins one after the other and restart Outlook after each reactivation
  • As soon as Outlook refuses to restart, you will know that the most recent reactivated add-in is defective
  • In this case, reenter the safe mode, and then deactivate and completely uninstall the add-in to resolve the problem

Repairing a faulty Outlook profile

If the previous method is unsuccessful or you still cannot open the Outlook window, even in safe mode, it could be that your profile – more specifically your “personal folders file” (.pst file) – is defective.


A .pst file contains your data files, in other words all e-mails, calendar entries, contacts, tasks, and notes that are associated with your Outlook profile. A standard outlook.pst is created the first time Outlook is started. However, you can create .pst files on your own, for instance to generate a back-up copy of your archived e-mails.

To confirm this speculation, you can try the following tricks:

  • Depending on your operating system: In the start menu, click “Control Panel,” or type “Control Panel” into the Windows search bar and then click on it
  • In the control panel, click “Mail” (the exact name of the label may vary)
  • When the dialog box “Mail Setup – Outlook” opens, click on “Show Profiles”
  • Click on “Add”
  • Follow the instructions to create a new profile, then click “Finish”
  • Under “When starting Microsoft Outlook, use this profile,” choose the “Prompt for a profile to be used” option and click “Ok”
  • Start Outlook

If you’ve done everything correctly, Outlook will start with your new profile. This proves that the issue stems from your original profile. Using the “Inbox Repair tool,” which is pre-installed on your computer along with Outlook under the name scanpst.exe, you can restore damaged data files.


The scanpst.exe tool searches through your data files (meaning your e-mails, calendar entries, contacts, tasks, and notes) for issues. If it finds an unreadable or damaged section of data, it will automatically remove it. It is therefore possible that several data files are lost during this restoration. However, this is the best solution according to Microsoft, because the files in question are already irreparably damaged.

As scanpst.exe is deeply hidden in Windows’ directory structure and is sometimes difficult to find, Microsoft offers a so-called easy fix solution to solve problems regarding your .pst file. This functions as follows:

  • On the linked website, scroll down to the “Here’s an easy fix” paragraph under the “More Information” heading, and click the “Download” button to download the scanpst.exe file
  • Open the file once the download is completed (administrator permission may be necessary to do so)
  • Follow the instructions

Microsoft keeps easy fix solutions (called “Microsoft Fix it” until September 2016) for a wide range of issues at the ready online, suited for all operating systems from Windows Vista onward. Here you can also find solution approaches for issues with older operating systems.

If you would rather manually run scanpst.exe, you must search for the tool in Windows Explorer for the time being. If your primary hard disk is called “C:” the storage locations for each operating system and version of Outlook can be found here:

Outlook version and operating system Storage location of scanpst.exe
Outlook 2016 (64-Bit, Click-to-Run Installation) \Program Files (x86)\Microsoft Office\root\Office16
Outlook 2016 (32-Bit, Click-to-Run Installation) \Program Files\Microsoft Office\root\Office16
Outlook 2016 (64-Bit, MSI-based Installation) \Program Files (x86)\Microsoft Office\Office16
Outlook 2016 (32-Bit, MSI-based Installation) \Program Files\Microsoft Office\Office16
Outlook 2013 (64-Bit, Click-to-Run Installation) \Program Files (x86)\Microsoft Office 15\root\office15
Outlook 2013 (32-Bit, Click-to-Run Installation) \Program Files\Microsoft Office 15\root\office15
Outlook 2013 (64-Bit, MSI-based Installation) \Program Files (x86)\Microsoft Office\Office15
Outlook 2013 (32-Bit, MSI-based Installation) \Program Files\Microsoft Office\Office15
Outlook 2010 (64-Bit) \Program Files (x86)\Microsoft Office\Office14
Outlook 2010 (32-Bit) \Program Files\Microsoft Office\Office14

Double-click on scanpst.exe (or rather, SCANPST) and proceed as follows:

  • Enter the path and the file name of your personal data file (.pst) or click “Browse” to find the file via Windows Explorer
  • Under “Options,” choose “Replace log”
  • Click “Start”
  • If issues are discovered during the inspection process, the tool will request a reparation

Your .pst file is now repaired. Now all that is left to do is to transfer the restored files into a new Outlook profile:

  • Start Outlook
  • Create a new .pst file by clicking “New Items” in the top left, then clicking “More Items” in the drop-down menu that appears, and finally clicking on “Outlook Data File”
  • Pull up the folder list on the left side with the key combination [Ctrl] + [6]
  • Look inside the “Lost and Found” folder in your old profile to verify which data files were fully restored and which were lost during the reparation
  • Next, pull all restored data files into your new profile
  • The “Recovered Personal Folders” .pst file can now be deleted, leading to the removal of the “Lost and Found” folder from your folder list

Outlook will not open: in case of an unknown error

Besides the widely-known error message, “Cannot start Microsoft Office Outlook. Cannot open the Outlook window,” unknown errors can also lead to a situation in which you cannot open the Outlook window. In this case, the following approaches can help.

End the OUTLOOK.EXE task process in task manager

It is sometimes the case that Outlook already experiences issues during its initial launch, and without providing an error message. For example, indications of this are that the PC slows down and that nothing happens even after the Outlook icon is clicked on several times. If a window does eventually open, “Not Responding” is probably shown in the menu bar. At this point, the only solution is usually to end the program manually:

  • Press [Ctrl] + [Alt] + [Delete] to pull up the task manager
  • Click on the “Processes” tab
  • Look for the OUTLOOK.EXE task process on the list, and click on the “End Process” button at the bottom left
  • Restart Outlook

Be careful not to accidentally end a different process, such as a system task process!

Update Outlook

If the issue has still not been resolved, you do not have to proceed with a new installation right away. It is possible that your issue has already been solved by Microsoft and that the updates necessary for the solution already exist.


The 2010 and 2007 versions of Outlook sometimes have compatibility issues with Windows 10. You can solve this by installing the newest Microsoft service packs and updates.

To update Outlook, it is best to use a Windows update:

  • Depending on your operating system: in the Start menu, click “All Programs” and then choose “Windows Update,” or enter the latter in the search bar
  • In the window that pops up, check if there are new updates for Windows and Office available and install them

Repair or reinstall Outlook

If none of the other solutions work, you can try Microsoft Office’s internal repair function:

  • Open the “Control Panel” (as previously described)
  • Click “Programs and Features”
  • Find “Microsoft Office” on the list and click “Change”
  • Follow the instruction – the best results are achieved with the “Online Repair” option

If none of the described solutions are successful, you can try to reinstall Outlook. Unfortunately, however, this is the most time-intensive method.

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