Cannot start Microsoft Outlook. Unable to open the Outlook window. The set folders could not be opened. The server is not available. Contact your administrator if this condition persists

Actually, this issue occurs as the current navigation pane in Outlook is not working properly. We can try to use the command "Outlook.exe /resetnavpane" to clear and regenerate the navigation pane for the current Outlook profile.

To run this command, click the Start pearl, in the Search box, type command. Right click on Command Prompt and press Enter. Run the following command in the Command Prompt:

"C:\Program Files\Microsoft Office\Office 14\Outlook.exe" /resetnavpane

Note: I assumed that your Office program is installed in C:\Program Files. If it is installed in other path, you can change the path.

If the problem persists after this, the best method is to create a new Outlook profile.

Method 3 : Command
Click Start>Run. In the Open field, enter > > outlook.exe /resetfolders > > Click OK. Make sure you include the space before the slash
Method 4 : Command Line Run Outlook from a command line with the /cleanprofile switch appended to the command. To find the correct command line, right click on a shortcut for Outlook and go to Properties. Copy the information in the Target field and Paste it to the command line. If there is already a command option, remove it and add /cleanprofile after the closing quotation mark. (Add a space before /cleanprofile) For example, go to Start: Run. . and enter something like "C:\Program Files\Microsoft Office\OFFICE11\OUTLOOK.EXE" /cleanprofile . Then add a new profile. Be sure to check the check box for "Set as default profile". Note: You cannot see this option unless you click on the "Options >>" button

Method 2: Delete the registry key

To do this, follow these steps.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 (http://support.microsoft.com/kb/322756/) How to back up and restore the registry in Windows

1.	Click Start, click Run, type regedit, and then click OK.
2.	Locate one of the following registry keys, as appropriate for the version of Microsoft Windows that you are using: HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem
3.	Delete the Profiles key under the Windows Messaging (Subsystem) key. To do this, right-click Profiles, and then click Delete. Click Yes to confirm the deletion.
4.	Exit Registry Editor, and then restart Outlook.