Suddenly some of my media files and folders contining them now have small padlock image on the right of their icons. What does this mean and how can I remove whatever is causing it?
The only side effect so far is that the affected files/folders are not appearing when I browse my laptop using the Windows 7 DLNA server. They do however appear if I use PS3 media server. Is this some kind of permissions thing?
The padlock icon over files come from Windows, not Opus.
It means those items have more strict permissions than the directory they are in, as far as I can tell. (I've never seen it properly documented but that seems to be how it behaves.)
In a shared folder, seeing that icon is a good indicator that the files probably won't be visible to all users that can see the share.
Reset the permissions on the files to remove the icon (but make sure it's appropriate to do so first; if it's data files or folders you made yourself then it should be safe but don't go messing with system folder permissions unless you know what you're doing).