I have a problem with opening .pdf files in Tb. The pdf itself opens normally in the inbox, but when I try to forward a message with an attachment, the pdf will no longer open. A message is displayed: The file C:UsersAdminAppDataLocalTempsmail-1.pdf cannot be opened because the associated helper application does not exist. Change the associations for this file type in preferences. I have the default adobe program set in the files and attachments preferences. I have no idea where to look for the helper applications mentioned in the message. Can anyone help?