Fix #1 - Pen Drive Hidden Files Recovery with Attrib Command You can run anti-virus software after getting back all hidden data. Tip: Do not run antivirus software to scan the virus infected pen stick because it probably removes all folder and files. How do you restore files hidden by viruses, malware or Trojan? Virus infection sometimes hides data in your pen drive but still occupy space. How can I see USB hidden files due to virus infection?' I cannot unhide the folder because the hidden tick is grayed out in the Properties of the folder. ' Folders in my pen drive are hidden because of virus attack.