Actually AC Edu will open AC Comercial and it will change the file to Educational if you save it.
The problem here is that you have to relink your library. In AC13 you were using the AC13 library, when you saved to AC12 the file is looking for the AC12 library. After opening the file you should get a window with a Library Loading report where you can relink the library to AC12.
Eduardo Rolón AIA NCARB
AC27 US/INT -> AC08Macbook Pro M1 Max 64GB ram, OS X 10.XX latest
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