ANSI PST was used in MS Outlook 2002 and its earlier versions while MS Outlook 2003 and above uses Unicode PST format. The size limit of ANSI PST was 2GB while the size limit for Unicode PST file is 20 GB.The only limitation that users face while using Outlook is data storage issue. In older version of MS Outlook ANSI PST file is created that allow storing data up to 2 GB in Outlook PST file, on the other hand MS Outlook 2003, 2007, 2010 and 2013 allows storing data up to 20 GB extendable up to 50 GB in Outlook 2013 and 2016.
An oversized 2 GB Outlook PST file is the most common reason for Outlook corruption. If your Outlook PST file get corrupt then use http://www.mannatsoftware.com/stellar-phoenix-split-pst.html
software which can split large PST file into manageable and smaller PST files as per the specific criterion like size, date, folder and email id, and protects them from any corruption issues because of file size limits.