The Inbox Repair Tool can be started with scanpst.exe. The location of this file is different for almost every version of Outlook and it sometimes also depends on which language of Outlook you have installed and even if you have it installed on a 32-bit version of Windows or 64-bit version of Windows.
To locate the scanpst.exe on your computer, the easiest way is to open File Explorer and search C:\Program Files or C:\Program Files (x86) for scanpst.exe
Once located, follow these instructions to check your PST file for corruption:
Also, do note that you now have a backup of your Outlook file that could be taking some space up.