I recently acquired a Canon ae-1 Program that is mostly in working condition.

The one problem that I have encountered is that the film will not advance past 13 exposures. The film advance lever will not move, and the shutter will not fire. I can press the rewind release, back the film up a bit and then fire the shutter, but it will not move past that 13th exposure. It just keeps re-exposing over the same shot. All exposures prior (1-12) come out with no problem whatsoever. I have run several rolls of film through the camera and it always gets stuck at the same time, though the rest of the film develops with no flaws.

Anyone have any idea what could be causing this?

I recently acquired a Canon ae-1 Program that is mostly in working condition.

The one problem that I have encountered is that the film will not advance past 13 exposures. The film advance lever will not move, and the shutter will not fire. I can press the rewind release, back the film up a bit and then fire the shutter, but it will not move past that 13th exposure. It just keeps re-exposing over the same shot. All exposures prior (1-12) come out with no problem whatsoever. I have run several rolls of film through the camera and it always gets stuck at the same time, though the rest of the film develops with no flaws.

Anyone have any idea what could be causing this?

Edit: When there is no film in the camera it will advance to 36 exposures without any problem.