This might happen because your PST or OST exceeds 2GB. You can try to keep them under this size to avoid feature errors. Also, it's advised to scan your computer with an antivirus utility and always keep a backup for the OST and PST files.
If the error still persists, you can use the Repair utility that is integrated in the Outlook software. To do this, close the Outlook program, if it's opened and go to C:\Program Files\Microsoft Office\OFFICE (this is the default location) and open the Scanpst.exe file. After you opened the utility, enter the name of the file that you want to scan in the box or search for it manually by pressing the Browse button. Click Start and wait for the utility to finish. If any error is found, you will be prompted to start the repair process. For more information regarding this, visit the following support page.