Some application or software recovery doesn't support all file extension. If you are infected with virus much better to fix and remove all viruses before you start recovering it.
Or you might be infected with ransomware where some important files are hidden.
I recommend you to try Kaspersky they have a free trial install it then update the database after that deep scan your PC.
If the kaspersky detects just disinfected them or delete. then after that, if you are infected with ransomware you need to use some tools to decrypt and shows all of your hidden files.
Check these links
https://www.kaspersky.com/anti-ransomware-toolhttps://noransom.kaspersky.com/dont worry it's free you don't need to pay.