Q: Can I put my .pst files on OneDrive for Business?
A: While this file type is not restricted, we do not recommend putting .pst files on OneDrive for Business.
Explanation: If you have a .pst file, the file is open at all times while you have Outlook open. The file is not closed until you close Outlook. If you experience any sort of network disruption (such as moving from one wireless access point to another), you could corrupt your file and lose data. The file would not be recoverable while in that state.