In this post I am going to talk about few steps that you can take when you cant open outlook.
Outlook manages a DB file in two different ways, depends on his connection to the server: exchange (OST), POP3/IMAP (PST).

Here you will find different ways to troubleshoot outlook loading problems with PST DB file and POP3/IMAP account.

Outlook PST:

Investigate possible issues with add-ins
Open outlook with command: outlook /safe.
You can do it easily with pressing “Windows+R” and type it in the “run” box.
If outlook’s loading is fine then it is not added in`s.
You can disable add-on`s via options -> trust center (depend on outlook version!), there you will see “add in`s” menu.
Rerun outlook without safe and see if it is working.

Recreate configuration file
If it still crashes, you need to find outcmd and outprnt files and delete them, outlook will recreate them on next open.
On Windows XP you will find them via:
c:documents and settings%username%application datamicrosoftoutlook.
On Windows 7 you will find them via:
c:users%username%roamingmicrosoftoutlook.
There is no worry in deleting those files.
Rerun outlook and see if fixed.

1st mail view
You can also try to delete 1st mail and rerun outlook. Sometimes it is a bad mail and preview pain cannot load the mail and outlook crashes.

2nd outlook run in background
The 3rd thing you can try is to see if there is another process named “outlook.exe” inside “task manager”. If so, press
“end task” and rerun outlook.
If none of the above methods helped you, it means PST corrupt or program malfunctions. You can try these steps:
Use scanpst.exe to scan your PST files for errors.
Use microsoft updates for new updates that may solve the problem.
Repair installation of office, if it is a new office you can go to the control panel and under “add/remove programs”, find Microsoft office and press “change”. Then choose repair (some version may require installation CD).

Outlook OST:

Investigate possible issues with add-ins

Recreate configuration file

2nd outlook run in background

Recreate OST file (offline cashe mode)

1. Windows+R and type control and press enter.
2. Go to Mail (if you cant find it, change view to classic/small icons).
3. Choose correct profile and press double click on him.
4. Left click “E-mail Accounts…”
5. Press “Change…”
6. Unchecked”Use Cached Exchange Mode”
7. Then Press “More Settings…”
8. Go to Advanced
9. Press “Outlook Data File Settings…”
10. “Disable Offline Use”
11. Press “Ok”>>”Ok”>>”Next”>>”Finish”>>”Close”.
12. Reopen outlook

If none of the above methods helped you …
Use Microsoft updates for new updates that may solve the problem.
Repair installation of office, if it is a new version of office you can go to control panel and under “add/remove programs”, find Microsoft office and press “change”. Then choose repair (some version may require installation CD).