Not sure if anyone else out there has this issue.

We run Pastel 2017, and just upgraded everyone to Office Pro 2016, there are no other issues except when a user (all users ) email a pdf attachment to themselves, either for review or to send on to other members of staff etc.
They cannot open them and they are corrupt and cannot be opened by anyone else. Edge gives the error "something is preventing this file from being opened" Adobe viewer will not open it nor any other pdf compatible viewer.

Heres the strange part is that if you go to sent items the PDF can be viewed there and any other Recipient other than the user whose email client is sending the PDF can open the file.

It is highly frustrating to my users even though I have shown then the workaroudn by viewing the sent items etc and I have spent hours with pastel they cannot help - the support tech actually told me he has a certain amount of calls to get through and couldnt spend anymore time on it (4 hours on the phone multiple remote desktops etc)

Any input would be great...

thanks in advance