No, its the com port driver. Windows and OSX insist on users using the included broken driver and so kill the driver from the download page.
The most optimal way to get things to work involves several "Cold Starts" of computers. A "Cold Start is where the hardware is powered off and left for a minimum of 3 mins to allow the capacitors in the ram to discharge, fully wiping the ram of retained data.
1, Delete existing com port driver,
2, Switch off and cold start machine.
3, Install driver,
4, Switch off and cold start machine.
5, Connect M5Stack cores and check the device managers for errors and that devices are recognised.
6, Switch off and cold start machine.
7, wait for machine to finish loading (give this 5 to ten minutes), then try connecting M5Stack BEFORE loading Arduino.
IF you reinstall arduino or any other IDE/Programming environment, you MUST Switch off and cold start machine before starting to program.
This is not a flawless method but is the most reliable method to get the driver to work on Windows and OSX!