Thanks, I figured I needed to import it with acrobat for it to work, but I thought I had to do it every time.
I'll update when I get the time to test it.
You have to import the XML data once with Acrobat before you distribute the form to others.
I found my problem, completely forgot the XML data isn't automatically linked to the form... I have to import it to the form every time I wish to fill it.
Is there any way I could make the document automatically import the XML data so we don't have to do it every time we open it?
The PDF-Preview also uses Adobe Reader so this cannot be the reason.
If you would share your form, we could analyse it.