Controlled folder access can stop untrusted apps from changing files in protected folders. It is one layer of protection, not a substitute for updates and a separate backup. Some legitimate apps may need permission after you turn it on.
If a trusted app stops saving to a protected folder, review the block notification before allowing the app. Do not allow an unfamiliar executable simply to remove a warning. Keep an offline or otherwise separate backup of important files.
Check the setting
- Open the Windows Security app.
- Choose Virus & threat protection, then Manage ransomware protection.
- Review Controlled folder access. If you enable it, check the protected folders and watch for notifications about blocked apps.
If a trusted app stops saving to a protected folder, review the block notification before allowing the app. Do not allow an unfamiliar executable simply to remove a warning. Keep an offline or otherwise separate backup of important files.