I have a completed design in software via STM32Cube and SW4STM32. I need to change a PIN in CubeMX. What will happen with my finished code when I GENERATE CODE within MX with the new single PIN change?

[TFlac]

I have completed a design using STM32F303RE Nucleo-64 board. Using STM32CubeMX and SW4STM32 (IDE). My design is done, I have build the design and there are no errors. Now I'm ready to physically download and test the design. I realize one of the PINS that was selected needs to be changed. When I go back and make this change in MX, what will happen on the IDE side. Will the MX overwrite the older source files? Note, I started the design by selecting the MCU and not the EVAL Board.

[Tesla DeLorean]

I wouldn't trust CubeMX further than I could throw it, if in doubt archive your project and .IOC files

Tool is apt to regenerate add/remove files, and lose anything outside USER tags.

I'm the wrong guy to ask..

If all the modifications you've done after the project creation by CubeMX were inside USER CODE tags, they should stay safe. Everything outside of the tags will be replaced based on the CubeMX project.