Submission + - Microsoft disbles preview in File Explorer to block attacks (bleepingcomputer.com) 1
For most users, no action is required since the protection is enabled automatically with the October 2025 security update, and existing workflows remain unaffected unless you regularly preview downloaded files.
"This change is designed to enhance security by preventing a vulnerability that could leak NTLM hashes when users preview potentially unsafe files."
It is important to note that this may not take effect immediately and could require signing out and signing back in.