How to FIX if outlook doesn't start

Problem

Outlook doesnt start

Solution:

1. Safe Mode

Safe Mode buttonIf Outlook worked correctly the last time and nothing has changed about your account configuration, then checking if things work correctly in Safe Mode is a good first step. Starting Outlook in Safe Mode will prevent some or all add-ins from being loaded, prevents several settings files from being loaded and turns off the Reading Pane.

To start Outlook in Safe Mode you’ll need to start Outlook with the “safe” switch;

Windows XP

Start-> Run; outlook.exe /safe

Windows Vista and Windows 7

Start-> type; outlook.exe /safe

Windows 8

Start Screen-> type; outlook.exe /safe

(just start typing, a search box will automatically become visible)

Windows 10

Start-> type; outlook.exe /safe

(just start typing, a search box will automatically become visible or type in the command in the Cortana Search box)

All Windows versions

Hold the CTRL button when clicking on the Outlook button to start it. You will get prompted whether you want to start Outlook in Safe Mode.


If it works in Outlook Safe Mode, the issue is most likely caused by an add-in, a corrupted settings file or the first message that is being displayed when Outlook is started.



If it doesn’t work in Safe Mode either,can continue with scanning your pst-file for errors. explaining that in below


2. Cannot open the Outlook window

getting the error “Cannot open the Outlook window” when trying to start Outlook, the error usually indicates that your Folder Pane or Navigation Pane settings holds a corruption.


Start Outlook with the resetnavpane switch;

Windows XP

Start-> Run; outlook.exe /resetnavpane

Windows Vista and Windows 7

Start-> type; outlook.exe /resetnavpane

Windows 8

Start Screen-> type; outlook.exe /resetnavpane

(just start typing, a search box will automatically become visible)
Windows 10

Start-> type; outlook.exe /resetnavpane

(just start typing, a search box will automatically become visible or type in the command in the Cortana Search box)


3. Reset dat-files

If you are using Outlook 2007 or previous, Outlook stores several settings in dat-files which get loaded upon startup. These files sometimes get corrupted and renaming them to .old could get you back into Outlook then. Outlook 2010 and later do no longer use these files so if you are using Outlook 2010 or later, you can skip this step.


Reset extend.dat and outcmd.dat by renaming them to .old when Outlook is closed. You can find the locations below;

extend.dat: This file keeps the settings of installed Exchange Client Extensions add-ins and their status.

Windows XP

C:\Documents and Settings\%username%\Local Settings\Application Data\Microsoft\Outlook\

Windows Vista, Windows 7, Windows 8 and Windows 10

C:\Users\%username%\AppData\Local\Microsoft\Outlook\

outcmd.dat: This file contains your Toolbar customizations.

Windows XP

C:\Documents and Settings\%username%\Application Data\Microsoft\Outlook\

Windows Vista, Windows 7, Windows 8 and Windows 10

C:\Users\%username%\AppData\Roaming\Microsoft\Outlook\

4. Disable add-ins

If Outlook works in Outlook Safe Mode but resetting your dat-files did not help, then the issue is most likely caused by an add-in.

Often, but not always, this is accompanied by an error similar to:


You can enable/disable Outlook add-ins in the following locations;

Outlook 2003 and previous
Tools-> Options-> tab Other-> button Advanced E-mail Options…-> button Add-In Manager…/COM Add-ins…

Outlook 2007
Tools-> Trust Center…-> section Add-Ins

Outlook 2010, Outlook 2013 and Outlook 2016
File-> Options-> section Add-Ins


5. Use scanpst.exe to fix Outlook Data File errors

When you use a pst-file, it could be that an issue with that pst-file is preventing Outlook from starting correctly.

Often this issue is accompanied by the message;

“Errors have been detected in the file <path to pst-file>. Quit all mail-enabled applications, and then use the Inbox Repair Tool.“


Use scanpst.exe to scan the mentioned pst-file for errors. The location of scanpst.exe depends on your version and language of Outlook.

Outlook 2016

32-bit Windows: C:\Program Files\Microsoft Office\Office16
64-bit Windows: C:\Program Files (x86)\Microsoft Office\Office16
64-bit Outlook: C:\Program Files\Microsoft Office\Office16
Office 365: C:\Program Files\Microsoft Office\root\Office16

Outlook 2013

32-bit Windows: C:\Program Files\Microsoft Office\Office15
64-bit Windows: C:\Program Files (x86)\Microsoft Office\Office15
64-bit Outlook: C:\Program Files\Microsoft Office\Office15
Office 365: C:\Program Files\Microsoft Office\root\office15

Outlook 2010

32-bit Windows: C:\Program Files\Microsoft Office\Office14
64-bit Windows: C:\Program Files (x86)\Microsoft Office\Office14
64-bit Outlook: C:\Program Files\Microsoft Office\Office14

Outlook 2007

32-bit Windows: C:\Program Files\Microsoft Office\Office12
64-bit Windows: C:\Program Files (x86)\Microsoft Office\Office12
Outlook 2003
32-bit Windows: C:\Program Files\Common Files\System\MSMAPI\<locale ID>\scanpst.exe
64-bit Windows: C:\Program Files (x86)\Common Files\System\MSMAPI\<locale ID>\scanpst.exe

When the scan is done and errors have been fixed, run scanpst.exe again until no errors are found anymore.


6. Recreate your mail profile

When your mail profile is damaged, Outlook often fails to start as well or you’ll find yourself encountering one error after the other.

Solution:
Recreate you mail profile via the Mail applet in Control Panel. You can first add a new mail profile without deleting or otherwise affecting your current configuration just to see if it will indeed solve your issue. If so, you can easily migrate your Outlook data file from the broken mail profile to the newly created one.