I have been using SimCity4 Startup Manager without any problems for a long time. However, today, all of the saved Region Profiles no longer show up when I click on the Region or City name. The only choice it gives is "load without plugins." You can still create a new profile. Also, it is no longer possible to swap the view to the Region Profiles list view.
The problem appeared to occur after I mistakenly loaded the game through the SimCity4 Rush Hour iconrather than the Startup Manager. I don't know if that somehow messed up the settings. Would greatly appreciate it if anyone has any suggestions on how to relink the saved Profiles to the Startup Manager. Otherwise all of my cities are effectively useless.
The SUM profiles are stored in the "SimCity 4 StartupManager.cfg", which is placed in "My Documents\SimCity 4". Maybe you accidentially deleted this file, or it got corrupted somehow. I had this once when my computer crashed while playing the game. I don't know if there's a way to recover the profiles, other than re-creating them manually, but it might be a good idea to backup the "SimCity 4 StartupManager.cfg" now and then. If you're lucky, the file is not entirely corrupted; try to go to the region management window and check your regions if the profiles are still there. If you're using a profile in more than one region, you can copy it by dragging and dropping the profile name over the target region name.