Hi,
I'm quite new to this forum. Originally I'm a mac/linux user. Today one of my friends asked me for help. I spent all the day searching and researching. We even tried Avast antivirus, but no success. They have a Windows server 2008 in their small office and have a bunch of files shared on it. Since this morning, all word, excel and pdf files are opened and saved. Last modified date time of them shows that. Their extensions remained unchanged. When trying to open them on any of workstations (Windows 7) a message received saying that file encoding has changed. We even tried to upload them into Google drive and open them using cloud based software. Again unsuccessful. I also tried to use 'open and repair' in Microsoft Word. It didn't work too. Errors screenshots are attached.
Thank you for your help in advance!