all my PDF attachments when saved/opened became invalid empty 0 bytes files

Hello, I have problem opening/saving PDF attachments. Recently I started to also have troubles with ".doc" attachments. If I want to open the PDF attachment in Thunderbird I get an blank page. If I want to save it, the saved file is empty and in folder it shows 0 bytes although in the message the attachments the file has the right size. If I choose open with Acrobat reader , absolutely nothing is happening, the Acrobat do not open, now file is displayed. Other colleagues can open the same message in Thunderbird and see/save pdf attachments without problems. I reinstalled both Thunderbird and Acrobat reader without any change What else should I try? I attach 2 screenshots. ( recently I started having troubles with ".doc" attachments as well) Thank you, Mihai