@zackng97 said in fatal error: pgmspace.h: No such file or directory: Error compiling for board Arduino Pro or Pro Mini. In your error log it says you are compiling for arduino pro "Error compiling for board Arduino Pro or Pro Mini." I imagine since your on the m5stack forums that you are not trying to program an arduino board. The m5stack board definitions and libraries need to be installed first and then the m5stack device selected in the board list and also the port must be correct. please see this video on how to get started with m5stack in the arduino ide https://www.youtube.com/watch?v=U2es-l4z2Zg