I myself faced this issue and my secure folder was locked out after numerous attempts and with below steps, I was able to resolve the issue.
1) Install APK Analyzer from playstore 2)open apk analyzer, Search for the app "Secure Folder" and click on it 3) Now goto the option called "activities" and select the activity "com.samsung.knox.securefolder.keyguard.KnoxKeyguardSamsungAccountBridge" 4)click on the play button on the right side and it will ask you to enter samsung account credentials 5) Post entering the credentials you will be taken to secure folder lock type settings 6) You can change your lock type and PIN/Password or Pattern from this page 7) Also make sure to enable the option "Reset with Samsung account" at the bottom. 8)Now open the secure folder app and you should see a forgot password option available now
