Fix/repair oversized Outlook PST file?

And also for reference Microsoft does not support pst files that are larger than 2GB in size, they can be corrupted really easy.
The thing with the PST file is that it is a database file so even if you throw away a multitude of mails from within the PST file the size will still be the same. You indeed have to compact it. This can also be done in Outlook itself ( see info below). But as said, because the file is this large you might corrupt it. I would suggest creating a new PST file and copy information into it until you reach 2GB and then create a new one. Do this until all mails are moved. Even then you might want to try and compact the file.

On the File menu, click Data File Management.
Click to select your Personal Folder, and then click Settings.
On the General tab, click Compact Now.
Click OK, and then click Close.

Make use of Recovery Toolbox for Outlook

Software can be found at:-
https://repairoutlook.recoverytoolbox.com/

Hi
Oversized PST files can cause a lot of trouble and even loss of data. I would like to refer to a blog that will help you out.
Read now- http://www.how2repairoutlookpst.com/blog/repair-oversized-pst-file/
This blog contains a method to repair your oversized PST files without any hassle. This will be really helpful to you.

Hello If anyone wants to look at the best way to repair oversized PST files then I would be suggested trying the KDETools PST Splitter.
Featured:
This tool split the large PST files based on date, size, year and folder.
This tool split the large PST files in ANSI and also UNICODE Version.
It distributes the large PST files without changing original data.
It split the large PST files without installing MS-Outlook.
This Splitter supports all the Windows Version and Outlook Version.

More Info: http://www.pst-splitter.com/

I will suggest you to use Kernel for Outlook PST Repair Software to fix or repair oversize Outlook PST file.