sumegh savant wrote:

you can create a common pst file on c drive in a folder and make it
the default mail delivery loctaion on both users.But thats not
recommended as there is 100% fear of crashing your outlook pst and
looisng you data. Even if you do that make sure both users are not
logged in at same time accessing same time

The OP indicates from the description that this is what's happening
already - i.e., the PST is being shared and the second user doesn't have
permission to the PST file.
--
Brian Tillman