Office & productivity software: Outlook 2007 Won't Open

Cannot open your default email folders. The file xxxx.ost is

Problem

"The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action"

or

"Cannot open your default email folders. The file C:\Users\user_name\AppData\Local\Microsoft\Outlook\outlook.ost is not an ofline folder file.

Some common examples are:

1. In Outlook, you haven't set the email account for accessing the Exchange mailbox correctly.

2. In Outlook, you delete the email account for the Exchange mailbox.

3. In Exchange server, the Exchange mailbox, or the email account for the Exchange mailbox is disabled or deleted.

4. There are communication problems between the Outlook and the Exchange server.

5. You don't have an Exchange email account at all. And your email account is based on POP3, IMAP, HTTP or mail servers other than Exchange server. But you set your email account as Exchange-based by mistake.

5.2 If your Exchange mailbox or email account doesn't exist any more, or you don't have an Exchange email account at all, or the instructions in 5.1 don't work, then your current mail profile is incorrect, you should delete it and create a new one, as follows:
5.2.1 Click Start, and then click Control Panel.
5.2.2 Click Switch to Classic View if you are using Windows XP or higher versions.
5.2.3 Double-click Mail.
******If this is Windows Vista 64Bit, then go to Control Panel and click on View View 32-bit Control Panel Items and after that you can see the Mail Icon.

******If still you are not able to see the Mail Icon or you are using Windows Vista 32-Bits, then the Outlook is not set as default program for e-mail. To set the Outlook as default email program, do the following steps: -
1. Go to Control Panel,
2. Click on View Classic Icons
3. Click on Set Default Programs
4. Select the Microsoft Office Outlook in the list in left side.
5. Now, click on Set this Program as default.

5.2.4 In the Mail Setup dialog box, click Show Profiles.
5.2.5 Select one of the incorrect profile in the list and click Remove to remove it.
***Option: Click properties -> Click email accounts -> highlight email account/double click and edit. May be better to remove and create a new one as detailed below:
5.2.6 Repeat 5.2.5 until all incorrect profiles have been removed.
5.2.7 Click Add to create a new profile and add email accounts according to their types.
Note: you may need to plug in all POP/IMAP email account settings/mail server settings/passwords
5.2.8 Start Outlook, you should find that the problem disappears.