I have a TIFF file that's locked my boss sent me via email and need to edit it. How can I do this and what program do I need to have to do so?
It's very simple to unlock the file. If you have Photoshop, open the file and go to Image > Mode. You will see that the Indexed color is selected. Choose RGB color and apply the changes. Go to the Layers section and double click the layer and it should be unlocked.
If you don't have Photoshop, download a trial from the official website: http://www.adobe.com/downloads.html