How to Resolve Error 15003 of Microsoft PST File?

This article was published in 2015 and updated in October 2026.

With Microsoft Outlook, all your emails, contacts, calendar entries, and tasks are saved on your computer. The Outlook mailbox items that are saved on your computer are stored in Outlook Data File, which is known as Personal Storage Table (PST) File. If you are using Microsoft Exchange account, then all your mailbox items are delivered and stored on the mail server. On the other hand, when you use IMAP, POP3, or web based email account, then your mailbox data is stored on your computer in PST file.

The PST files have size constraint that varies with the version of Outlook. Outlook 2002 and earlier versions support PST files of 2GB; Outlook 2003 and 2007 use a newer format with a default limit of 20GB, and Outlook 2010 and later allow up to 50GB by default. Due to their complex structure and their location on local hard drive of your computer, PST files are prone to corruption. Generally, a corrupt PST file throws an error message when you try to extract data from it or try to access it. A practical example for this situation can be a better way to understand it:

An error message that a corrupt PST file throws while trying to access data from it is:

“Error 15003 when processing PST files”

This error message normally maps to MAPI error 0x80040600. The error number 0x80040600 says

MAPI_E_CORRUPT_STORE, which means corrupt PST file. The corruption of PST file occurs due to various reasons, which vary from PST structure corruption to issues with local hard drive. Since in most of the cases, the Inbox Repair Tool of Outlook resolves your problem, using this tool for such situations can also be beneficial.

The Inbox Repair Tool is the inbuilt utility of Outlook that diagnoses and repairs errors in Outlook PST file. It scans the file to make sure whether the structure of the file is intact or not. If it is not, then the tool resets it and rebuilds the headers. Every version of classic Outlook for Windows includes its own version of the tool, up to Outlook 2016, 2019, 2021, 2024 and Microsoft 365. (The “new Outlook for Windows” works differently and doesn’t use the Inbox Repair Tool.)

It is installed with the installation of Outlook and is located at:

“drive:\Program Files\Microsoft Office\OFFICE12” for Outlook 2007. In current versions (Outlook 2016 and later, including Microsoft 365) look in “C:\Program Files\Microsoft Office\root\Office16” — or simply search for scanpst.exe in File Explorer.

Use the following steps to repair and resolve the error (including the above mentioned one) with this tool:

• The very first step is to exit Outlook, if it is running.
• Double click the scanpst.exe file (the Inbox Repair Tool is found in this form only).
• In the box ‘Enter the name of the file that you want to scan box’, enter the name of the PST file that you want to scan; or you can browse for this file for checking it.
• For specifying the scan log options, click ‘Options’, and then select the option that you want.
• Click ‘Start’.
• If you find errors after the completion of the scanning process, then you will be prompted to start the repair process for fixing the error. Note: A backup file of your PST is created during this process. For changing the name or the location of this file, click ‘Enter name of backup file’ box, enter a new name, and ‘Browse’ for the location where you want to save it.
• Click ‘Repair’.

Run the tool several times if it keeps finding errors, until the scan comes back clean. With these simple steps, your PST file will usually be repaired; however, if this process too fails to do any needful to you, then use of a professional PST recovery tool is recommended. A reliable tool repairs corrupt or damaged PST file and restores all its data without causing loss. One such tool is Stellar Phoenix Outlook PST repair. This tool supports all version of Outlook including Outlook 2013 & Outlook 2010. It repairs your corrupt pst file in minimal efforts.