What computer operating system is your Premiere Elements 12 running on? Have you updated 12 to 12.1 Update via a project's Help Menu/Update? If not, please do so.
I still can't switch from organizer mode to editor mode to edit a file (photo).
Just how are you trying to do that...
a. Are you in the Elements Organizer 12 workspace, right clicking the photo's thumbnail, and selecting Edit with Premiere Elements Editor
b. Something else.
Is there an error message that results when you try to switch "from organizer mode to editor mode" and cannot?
When you mention "....to edit a file (photo)", I wonder if you are not trying to get to Photoshop Elements 12 Editor, not Premiere Elements 12 Editor, from the Elements Organizer 12.
Please supply a step by step of what you are doing so that we can be sure that we are in sync on the details that we are using to work through your issue.
After successfully installing and registering both adobe elements 12 and premiere elements 12 in my Windows 7 operating system a few weeks ago from now, I still have no luck running both programs. And just today, when I try to open the adobe photoshop elements 12, it didn't open the program and instead a pop-up menu window show stating "Sign in Required", and after entering my adobe ID in the Sign In Now nothing happen. And even I can open my adobe premiere elements 12 only in the Organizer mode and not able to switch to the Editor mode for editing. I hope you'll have an answer to this problem of mine and I really do appreciate all the help that you can give.
This sounds like an activation issue.
Let us focus on Photoshop Elements 12 and its Elements Organizer 12 first.
Rename the SLCache Folder and SLCache Folder according to the how to in the following blog post.
Let see what impact this has on Photoshop Elements 12. If we get lucky it may help the Premiere Elements situation as well.
Fight now, focus Photoshop Elements.