When you encounter various problems when using your Outlook, you can diagnose the problem and find out the solution.

First of all, it is possible that different reasons will cause the same problem or symptom, so you need to determine the actual reason before find the solution for it. The common reasons are:

  1. Some faulty Outlook Add-Ins cause the problem.
  2. Your Outlook PST file is damaged or corrupt.
  3. Your Outlook profile is corrupt.
  4. Your Outlook installation or configuration is incorrect.

To whether the problem is caused by reason 1, you can first disable all the Add-Ins in Outlook, as follows:

  1. Start Outlook.
  2. Click “File” > “Options”
  3. In Outlook Options dialog, from left sidebar, click”Add-Ins”.
  4. In the main window, click “Go” button in the bottom of the window.
  5. In COM Add-Ins dialog, unselect all the Add-Ins, then click “OK” button.
  6. Close Outlook and then restart it.

This will disable all the Add-Ins in your Outlook. If the problem disappears after restarting Outlook, then the problem is caused by reason 1. Otherwise, you need to continue with the next procedure.

  1. Close Outlook.
  2. Find your PST file by following the instructions at this article.
  3. Copy your PST file to another computer with Outlook installed.
  4. Start Outlook in the new computer, then use “File” -> “Open” -> “Outlook Data File”, to open the PST file.
  5. If the PST file cannot be opened, or there are some error messages when opening the file, then your PST file is corrupt so we can confirm your problem is caused by reason 2, otherwise, if the PST file can be opened without any problems, then your PST file should be healthy and the reason is 3 or 4.

For reason 2, you can check this article to fix the problem.

For reason 3 and 4, you need to continue the analysis procedure, as follows:

  1. Go to Start Menu > Control Panel > Mail.
  2. Click “Show Profiles“
  3. Click “Add” to add a new profile.
  4. In the lower part of the dialog, set the new profile as “When starting Microsoft Office Outlook, use this profile”
  5. Select the new created profile, then click “Properties“
  6. Add the PST file to the new profile.
  7. Restart your Outlook. If your Outlook problem disappear, then the reason is 3 and you have fixed your problem. Otherwise, the reason is 4.

For reason 4, then your Outlook installation is incorrect and you may have to reinstall Outlook or even the whole Office suite. Or if you have a backup of your system, then you can restore your system to a backup point when you can use Outlook without problems.