Windows folder or file padlock icon removal

If the ownership of a folder is SYSTEM, starting with Windows 7, newly added files will be "locked"  and the padlock or file lock icon will appear until those files are specifically shared with "Everyone" or some desired group of individual users or until the folder is shared differently in terms of its ownership on multi-user systems.

Note the padlock (also commonly referred to as a file lock) icon

Until the file is shared or the ownership of the folder is changed, the newly added file will be accessible/readable by the PC on which it was installed but not by other users that connect to that PC.

If SYSTEM is  listed first (in the above example, it is listed second) , then newly added files may be  be "locked" until they are specifically shared, or until a Users or Everyone group is added. Click on the Advanced button to view, in this case, the folder's owner.

Here is a helpful Microsoft technet article to help with on changing file or folder ownership:

https://technet.microsoft.com/en-us/library/cc753659(v=ws.11).aspx

(Take Ownership of a File or Folder, applies to Windows 7, WIndows Server 2008 R2)

As indicated via the MS article, you resolve by opening Windows Explorer, then locate the file or folder you want to take ownership of, right click on either the file or the folder, choose properties and then click on the security tab.  Under Advanced click on the Owner tab (in Windows 10 click on the clickable Change label  to the right of Owner).