I had the padlock on a folder after trying to share it with the Homegroup feature. Apparenlty if you remove the HomeUser group from having Read & Execute permission to a folder the lock overlay will appear
And I found this fix on another forum so I will include it here. It sorted me out ok.
You can remove the lock overlay in this case by resetting the permissions to be inherited, and removing all permissions that are not inherited.
Right click the folder, click Properties
Click the Security tab
Click Advanced
Click Change Permissions
Check Both boxes to Include inheritable permissions, and to Replace all child object permissions
Click Apply then click Yes
Wait for the list to refresh
Remove all permissions that say <not inherited>
That should remove the Lock overlay.
You may need to Uncheck Use Sharing Wizard in | Folder Options | View tab to see the Security tab, and may have to boot to Safe Mode as well if running Home Basic or Premium.