I have backup the .pst files from every client. But now I need one backup. I
have tried to open the pst file in a new outlook. Everything worked fine. I
have all e-mails, contacts etc. But the custom fields are all gone.

I have read many Threads here. They told me only to copy the pst file,
because the import option cannot import custom fields. But the other way
doesn’t work to.

How I get the information in the custom field back. the only backup i have
is the .pst file.