Corrupt OST files in Outlook 2003

Hi

Unfortunately my previously attempt to get an answer did not give an answer
on my question.

I have lately experience that some of my users Outlook.ost files is being
corrupt.
Have use Scanost.exe to repair the file without any luck.
My question, how is the local *.ost file being corrupt? And is there other
tools that is more powerful than the on that comes with Office 2003?

To create a new *.ost file is not an option since I have users all over the
world and only one Exchange server.
This one is located in our main office.

Looking forward to hearing from you.

Kind regards