Go Down

Topic: Mac USB serial port suddenly disappeared (Read 2842 times) previous topic - next topic


Hi guys,

Currently having issues with the USB ports not showing up on my Arduino software.

I have been working with Arduino for a year on the same Mac, yesterday I experienced a crash and white screen on boot up, after booting in safe mode everything was working fine yesterday - including the serial port connection. I usually access /dev/tty.usbmodem621

I have tried resetting the board, restarting, multiple usb ports, etc, also have tested multiple arduino boards (I'm using Arduino Uno) one older with existing programming loaded, and one brand new, as well as multiple cables. The result is always just the on lights (receiving power), but no reaction from the software.

Currently running OS X V10.9.5, 2GB RAM, 2 Ghz Intel Core 2 Duo, 2008 Macbook. My Arduino software version is 10.0.5

Apologies if any of my terms are odd. I'm not a technical expert. I'm a BFA student and I use arduino to control lighting and motors in art projects.

Wondering if anyone has experienced a similar issue to me.



ould guess that another process has grabed the USB port if you crash OSX thjen it generally recovers with the last process states.

Whats the result of using the terminal command

ls /dev/tty.*

This will identify what the USB ports are currently set up by..

Without an Arduino connect you qwuill usually get

/dev/tty.Bluetooth-Incoming-Port   /dev/tty.Bluetooth-Modem


ls /dev/cu.*

produces ..

/dev/cu.Bluetooth-Incoming-Port   /dev/cu.Bluetooth-Modem


Hi guys, actually i have the same problem, it doesn't has the usb port available to connect my arduino's board to the Pc.

Tool - Port - Modem Port, Bluetooth Port, Wireless…

It doesn't has the Port COM1 or COM4 Available

What should i do?



As Isaid above what the result of the commands\


ould guess that another process has grabed the USB port if you crash OSX thjen it generally recovers with the last process states.

Whats the result of using the terminal command

ls /dev/tty.*

This will identify what the USB ports are currently set up by..

Without an Arduino connect you qwuill usually get

/dev/tty.Bluetooth-Incoming-Port   /dev/tty.Bluetooth-Modem


ls /dev/cu.*

produces ..

/dev/cu.Bluetooth-Incoming-Port   /dev/cu.Bluetooth-Modem

My results (also with unresponsive Arduino plugged in) are this:

/dev/tty.Bluetooth-Incoming-Port   /dev/tty.name-1
/dev/tty.Bluetooth-Modem      /dev/tty.name-Dial-UpNet-1

/dev/cu.Bluetooth-Incoming-Port      /dev/cu.name-1
/dev/cu.Bluetooth-Modem         /dev/cu.name-Dial-UpNet-1

Name is the Laptop's name, it's the full name of a previous owner that isn't myself, so I've removed it to respect their privacy.


Its probably worth trying to plug a memory stick or something into that usb port to check it quickly.

After that, you could read the kernel panic report and see what caused it, but to be honest I doubt it'll help much (you can google how to read them, its not obvious).

I spent ages investigating my kernel panics, they seemed to be linked to how the IDE interacted with Java/USB, which I believe changed to jssc . Usually i hate it when you get the stock reply of 'upgrade to the current IDE', but in this case that seems like a valid first step.


Mar 03, 2015, 10:47 pm Last Edit: Mar 03, 2015, 10:52 pm by SarahMohawk
Upgraded to the newest version just after I wrote the initial post - It hasn't helped. Some new ports opened up at some point when I was messing around, this is the error I get for using /dev/tty/name-1:

avrdude: ser_open(): can't open device "/dev/tty.name-1": Resource busy
ioctl("TIOCMGET"): Inappropriate ioctl for device
Problem uploading to board.

As for the kernel panic reports I couldn't find a recent enough file in /Library/Logs/

EDIT: Just thought I'd add since the error appears to be that the ports are 'in use', there isn't any software that should be blocking them. I haven't added anything new and I've looked at my firewall. I also went into the lock files already, there were ones created on the day that the error occurred so I removed them, this didn't help.


Hi guys, just wanted to add an update on this issue - turns out that the new arduino's I got have the ch340G chip rather than a FTDI chip. I installed the relevant drivers, but it's still giving the same error on the clone device, although somehow the drivers enabled my FTDI devices to access the ports again. Presumably the vanishing serial port issue was brought on by plugging the new board in for the first time. Still having problems but i'm emailing with my supplier about it, will send further feedback when I have more time!


May 16, 2015, 06:38 am Last Edit: May 16, 2015, 06:40 am by MiketheChap
I had this issue as well on a brand new MacBook Pro as of this Spring (Yosemite). It's quite frustrating. Tonight I was trying to get the Adafruit Metro board (essentially an Uno) working. Same error as reported here: I wasn't seeing anything under the Tools|Port menu other than "Serial Ports" and two Bluetooth items.

I tried:

  • Resetting the board
  • Restarting the Arduino IDE
  • Replugging the USB cables (I buy really good ones so I didn't think that would be it)
  • To this point, I did not have success | After this point somewhere (don't know where), I started seeing a non-Bluetooth serial port.
  • Since I was starting with example sketches, I read somewhere that you should save whatever examples sketches you open to your sketchbook, so I did that.
  • I rebooted my Mac and reloaded the Arduino IDE
  • For sure at this point I had a new serial port and was able to upload sketches.

I remembered that recently, I'd been installing a newer version of Python and doing other utility kinds of things on Terminal. I wondered if TGSuperSpec wasn't right: that maybe some of my ports had been hijacked while I was hacking around with stuff.

I am not really sure what fixed it nor why. I just figure that several problem reports can help narrow it down. This is my attempt to help with that.


I solved this problem.  Maybe this post will help others.

I've come across this problem a couple of times.  I literally searched for hours for the answer and ended up using several suggestions.

Each scenario I solved is documented below as 'Scenario A' and 'Scenario B':

Scenario A

Plugged in a new Arduino Uno R3 board, successfully compiled the standard "Blink" sketch.  When I tried to upload it to the board, I got this message:

Sketch uses 1,066 bytes (3%) of program storage space. Maximum is 32,256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2,039 bytes for local variables. Maximum is 2,048 bytes.
avrdude: ser_open(): can't open device "COM1": No such file or directory
ioctl("TIOCMGET"): Inappropriate ioctl for device
Problem uploading to board.  See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

The Port Options in the IDE (Tools--> Port) only showed  /dev/cu.incoming-bluetooth-port

Here's what worked:

1. Downloaded and Installed the CH340 driver
2. Removed the FTDI drivers from my mac.  Apple recently installed a new utility that prevents removal of what it considers to be critical components. 

The process that enforces this rule is called csrutil. 

You'll have to disable this process to remove the FTDI driver.  Then you'll need to re-enable it when you are done.  This required a restart in recovery mode.  Here's how to do that:

    a.)  power off the mac then hold 'command'+R during the restart until the image of the apple appears.
    b.)  when the screen refreshes, click on 'Utilities' menu then 'Terminal.
    c.)  type csrutil disable
    d.)  Hit enter
    e.)  Restart  [Note:  You may be able to execute the next two commands in the terminal before restarting.  I just didn't test it that way.  If the system will allow you to, then by all means run all three commands one after the other THEN restart and you should be on your way.]

3.  remove the FTDI drivers by opening the terminal program again and entering the following command:
           sudo rm -R /System/Library/Extensions/AppleUSBFTDI.kext

Type in your password when prompted.

4.  Restore the apple csrutil by following steps a and b above.  Task c will be the same EXCEPT you'll type this instead:

        csrutil enable

   Then follow steps d and e.

When you restart the arduino IDE, you should see a more comprehensive list of ports besides just the bluetooth port.

Scenario B

This board was an import and clearly not an original Arduino/Genuino.  Attempts to load sketches resulted in this lovely error:

        Using Port                    : /dev/cu.usbmodem1421
        Using Programmer              : arduino
        Overriding Baud Rate          : 115200
avrdude: ser_open(): can't open device "/dev/cu.usbmodem1421": No such file or directory
ioctl("TIOCMGET"): Inappropriate ioctl for device

There was only one Port listed in the IDE, dev/cu.Bluetooth-Incoming-Port.

It had been a while since Scenario A had occurred and since then I'd installed a few OS updates.  Checked the drivers and low and behold, the darned FTDI drivers had RETURNED!!

I repeated the steps in scenario A above but the problem remained.

Then I installed an updated board configuration from arduino and it worked!  Testing on the first board I'd used under scenario A were successful as well.  Here's what I did:

1. In the IDE go to Tools-> Boards -> Boards Manager
2. I installed 'Arduino SAM Boards (32-bits ARM Cortex-M3) by Arduino version 1.6.8
3. Unplugged and replugged the USB cable into my arduino.
4. In the IDE go to Tools -> Port.  The /dev/cu.usbmodem1421 was listed as a port option.  Selected that.
5. Uploaded my sketch.
6. Bask in glory of SUCCESS!

I hope this was helpful to you.  I spent two days on Scenario A and 3 hours on Scenario B.

Go Up

Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

via Egeo 16
Torino, 10131