For an absolute solution to convert MBOX to PST files, you should try to take a help of Kernel for MBOX to PST Converter Tool. By using this software, one can easily and quickly transfer all kind of MBOX files to PST files without facing any hassle.
For more visit http://www.free.mboxtooutlook.mboxtopst.org/
or
http://www.mboxtopstfile.com/