thanks for the answer.
At first: There something missing in my first part:
OS: OS X 10.11.6 (15G31)
I did exactly what you and the other forum-guys proposed (driver-conflicts and troubleshooting on the mac-usb-serial-HP). I also bought the mac-usb-serial-USB-serial drivers.
What I did since my last login with a little more detail:
1. Kextunloading and removing all USB-serial-drivers
I unloaded and removed all USB-serial-drivers using the terminal app and the mac-usb-serial-HP-protocol. After the reboot I had no USB selectable, off course. I have three possible connections: tty.bluetooth-incoming-port, Makeblock-ELETSPP and iPhone-WirelessiApp.
2. USB-serial driver proposed by mBlock
I installed only the USB-serial driver proposed by mBlock. I find /Library/Extensions/usbserial.kext. After installation I restarted the macbook. Now …
mbot: When I physically connect the mBot via USB I find in the menu /Connect/Serial Port/tty.wchusbserial1420 as a possible USB-connection. When I run the connection I can upgrade firmware or reset the default program and after that the connection is lost - no way of re-getting it without quitting mBlock.
Arduino Uno: When I try to run a simple blinking program after successful connection it works perfectly on an Arduino-Uno.
But when I connect the mBot and run the same program (after successful connection) I get the following message: avrdude: ser_open(): can’t open device “/dev/tty.wchusbserial1420”: Resource busy
ioctl(“TIOCMGET”): Inappropriate ioctl for device
Maybe this is because on the mBot the last installed program is running over and over again (on the Arduino only once!)?! Is there a possibility to stop a program on the mBot by pushing some buttons?
2. mac-usb-serial-third party drivers
Now I remove /Library/Extensions/usbserial.kext with the following steps:
kextunload-order with message: sudo kextunload ./usbserial.kext
(kernel) Can’t unload kext com.wch.usbserial; classes have instances:
(kernel) Kext com.wch.usbserial class wch_usb has 2 instances.
Failed to unload com.wch.usbserial - (libkern/kext) kext is in use or retained (cannot unload).
Here it says having two instances?!? Can this be the source of the problem
rm-order: After this I "sudo rm -rf above and restarted the computer
Now I installed the mac-usb-serial-third party drivers. I find /Library/Extensions/osx-ch341.kext and …osx-pl2303.kext (no usbserial.kext) after restarting the computer.
Testing with the Arduino-Uno with mBlock: when I physically connect the Uno I can select in the menu /Connect/Serial Port/tty.usbmodem1421 and the blinking program runs perfectly, no problems with the connection! The app Systeminformation also recognizes the Arduino as a communication tool.
Testing with the Arduino-Uno with the Arduino-Software: it works as fine as above.
Connecting the mBot: when I physically connect the mBot I can select in the menu /Connect/Serial Port/tty.Replea-CH341-00002014 (no tty.usbmodem1421) and nothing works anymore. I cannot connect mBlock and mBot!
These are the results of three hours of troubleshooting. I have no more ideas!!!
HELP and thanks for your forum-support!
Best wishes from Germany!