Cannot open Serial monitor

Hi there,

I am trying to install a microSD card on my Andruino Yun, as per the instructions in here: http://arduino.cc/en/Tutorial/ExpandingYunDiskSpace. However, when I select "Tools->Serial monitor" nothing happens (I expect a window to pop up).

I am using Arduino 1.5.7 (also tried 1.5.6r2 but didn't work either).

Any help would be much appreciated.

Cheers

Cristian

What operating system are you using?

Oops, I forgot to mention. I am using Ubuntu 14.04 (64 bits).

The preferences dialog should have a path to the preferences file, follow that and open it.

Look for last.serial.location. Make sure it has sane values like

455,469,500,500

Interestingly, there is no last.serial.location entry in ~/.arduino15/preferences.txt

BTW, I forgot to mention that I can run examples on the board without a problem (for example the "blink" example that flashes an LED). It's just the serial monitor that I can't open.

In case it helps, I am pasting the entire preferences.txt files below:

board=yun
browser=mozilla
browser.linux=mozilla
build.warn_data_percentage=75
console=true
console.auto_clear=true
console.error.file=stderr.txt
console.length=500
console.lines=4
console.output.file=stdout.txt
editor.antialias=true
editor.caret.blink=true
editor.divider.size=0
editor.divider.size.windows=2
editor.external=false
editor.font=Monospaced,plain,12
editor.font.macosx=Monaco,plain,10
editor.indent=true
editor.invalid=false
editor.keys.alternative_cut_copy_paste=true
editor.keys.alternative_cut_copy_paste.macosx=false
editor.keys.home_and_end_travel_far=false
editor.keys.home_and_end_travel_far.macosx=true
editor.keys.shift_backspace_is_delete=true
editor.languages.current=
editor.linenumbers=false
editor.tabs.expand=true
editor.tabs.size=2
editor.window.height.default=600
editor.window.height.min=290
editor.window.width.default=500
editor.window.width.min=400
export.applet.separate_jar_files=false
export.application.fullscreen=false
export.application.platform=true
export.application.platform.linux=true
export.application.platform.macosx=true
export.application.platform.windows=true
export.application.stop=true
export.delete_target_folder=true
last.folder=/home/cperfumo/Arduino/YunDiskSpaceExpander/YunDiskSpaceExpander.ino
last.ide.1.5.7.daterun=1405385416
last.ide.1.5.7.hardwarepath=/home/cperfumo/Development/arduino-1.5.7/hardware
last.screen.height=900
last.screen.width=3200
last.sketch.count=0
launcher=xdg-open
platform.auto_file_type_associations=true
preproc.color_datatype=true
preproc.enhanced_casting=true
preproc.imports.list=java.applet.,java.awt.Dimension,java.awt.Frame,java.awt.event.MouseEvent,java.awt.event.KeyEvent,java.awt.event.FocusEvent,java.awt.Image,java.io.,java.net.,java.text.,java.util.,java.util.zip.,java.util.regex.*
preproc.output_parse_tree=false
preproc.save_build_files=false
preproc.substitute_floats=true
preproc.substitute_unicode=true
preproc.web_colors=true
programmer=arduino:avrispmkii
run.display=1
run.options=
run.options.memory=false
run.options.memory.initial=64
run.options.memory.maximum=256
run.present.bgcolor=#666666
run.present.exclusive=false
run.present.exclusive.macosx=true
run.present.stop.color=#cccccc
run.window.bgcolor=#DFDFDF
serial.databits=8
serial.debug_rate=9600
serial.parity=N
serial.port=/dev/ttyACM0
serial.port.file=ttyACM0
serial.stopbits=1
sketchbook.path=/home/cperfumo/Arduino
software=ARDUINO
target_package=arduino
target_platform=avr
update.check=true
update.id=-1239689784501005693
update.last=1405385418262
upload.using=bootloader
upload.verify=true

Next time, post that kind of thing with code tags .

Have you tried adding a last.serial.location?

Like last.serial.location=455,469,500,500

Awesome! It worked after adding that!
Where was I supposed to have read this? It didn't become apparent from reading the getting started guide, examples, etc.
Thanks a lot for your help!

1.5.x is beta.

im a newbie and im facing the same problem for my arduino mega as well.
i cant open the serial monitor it says the serial port(COM3) is already in use.

where could i find the last serial location? and where should i add it to?