• Step 1: Close Outlook. Completely. That means it has to be 100% NOT open; sometimes Outlook actually takes a little while to close after it disappears. If in doubt, press Control+Alt+Delete to pull up Task Manager, hit the Processes tab, click on every "OUTLOOK.EXE" listed and hit [End Process] for each.
• Step 2: Open the "Mail" control panel. Click on "Data files." You will see a list of Outlook data files that are currently loaded into the mail subsystem in Windows. You need to create a new data file, and be sure to give it a name other than "Personal Folders" at the top, so you won't get confused in the next steps. The other options you pick really don't matter; you can accept the defaults for everything and it'll be fine. Don't set a password for the .pst file unless you want to make your life painful, though!
• Step 3: After you see your new data file appear in the list, hit OK or Close to return to the Mail control panel. HIt the first button (it should say something about E-mail accounts), and if you get another screen asking what it is you want to do with E-mail accounts rather than just getting the list, hit the button for managing existing accounts and click Next. At the bottom, under the list of mail accounts, there is a drop-down box for the "default mail delivery location." CHANGE THIS to match the name of the new file that you created earlier. (If you have two "Personal Folders" entries, you didn't name it earlier, so choose the LAST file in the list and it should be the correct one.) Then click OK or Close.
• Step 4: Click on [Data files] again, and the new data file should have an indication that it is now the "default mail delivery location." This will then allow you to remove the old data file from the list, which is safe to do, so go ahead and toss it now to prevent possible confusion later. Click OK or Close after you've removed the old file from the list.
• Step 5: Close the Mail control panel. Open Outlook again. You may receive warnings about the things you've just changed; this is normal and you can simply click through them. You should now have a new, empty set of folders, with no contacts or mail whatsoever. The last step is to bring all of your old mail, contacts, tasks, etc. into the shiny new empty folders file. Go to File, then Import and Export. Choose to import from another program or file, and click Next. In the list, choose to import an Outlook personal folders file (.pst), and click Next again. If you are asked about how to import duplicates, choose to "replace duplicates with items imported" (though technically it shouldn't matter which you pick). When you finally receive a blank in which to specify the file to import, click Browse.
• Step 6: In case previous 5 steps can't assist you, then you may refer to https://www.repairtoolbox.com/outlookrepair.html Outlook Repair Toolbox
