@teastain Hi Terry, et al thx 1M for your effort helping me! I've just found the work around: As per "M5Stack Library won't install on Arduino IDE", CitrusPeel identified the issue: The package's name "MODULE_GRBL13.2" in library.properties should be "MODULE_GRBL_13.2" (underline instead of space before 13.2). So download M5Stack unzip it edit file "library.properties", line to "depends=M5Family,M5Module-4Relay,MODULE_GRBL_13.2,M5_BMM150" zip it and install zipped library restart IDE update now performed flawless @m5stack: awaiting M5Stack (0.4.6) to be released soon, as not all users having the knowledge on how to apply this "patch". Cheers, Marcus