Hi everybody,
I have a bug with my serial monitor : nothing happen when I want to open it !
The only thing that I can see is that a new window is open in my taskbar (cf picture), but I can't open it !
Even with the basic "AnalogReadSerial" code, nothing comes up...
My arduino device is recognised and at the good "COM port". Is it a bug of the IDE ? I'm using Windows 10.
Thank's guys...
Simon
What is your "good COM port" number ?
I presume the sketch uploaded correctly and without any errors ?
Also which board in particular ?
Hi and thank's for your answer !
By "good COM port" I wanted to say the one that is recognised by arduino. (it's written "Arduino Uno on COM 5"). I tried other COM but same problem.
No problem for uploading, if I test with the basic "blink led" code it works (the led blink), just the serial monitor doesn't appear !
My board is an Arduino Uno.
I tried to uninstall, it still doesn't work.
EDIT : With the Arduino IDE 1.0.x it works !
I really don't get it... ! Maybe some preferences in my IDE that blocks my serial monitor?
Thank's,
Simon
Any chance it's really opening the window "off screen"? Maybe your system has multiple monitors, or had 2+ monitors at some point and still is configured for a virtual desktop larger than your primary monitor?
Your picture clearly shows a COM screen at the side of the IDE screen.
Make sure the serial console screen settings MATCH those in the sketch.
eg. "Serial.begin(9600);" should be matched with the same speed in the serial monitor.
If you played with any of the other settings at the bottom of the serial screen you should default them back to NEWLINE and 9600.
Hi @pjrc and @ballscrewbob, thank's for your answer !
@pjrc I tried but I really can't find it... 
@ballscrebob, I agree it clearly shows that the com is running, but the thing is I can't access to it ! I can't click on the Monitor screen. I can't even see the configuration of the baudrate in my windows, as the window won't show up...
I'm thinking of a bug of the IDE, or a problem with the parameters of my computer... it's strange because it happened like that, don't know why !
It's kind of difficult to explain as it's more interactive, and I really don't get it.
EDIT : If I look closely, I can see in the small preview (cf my screenshot above) that the values are given ! the communication is working, but I can't display it.
Thank's guys !
What resolution are you running in on your computer ?
May not be the cause but the scale looks quite odd.
It's a 1080p, the screenshot is in bad quality I guess 
Just as a test can you lower the resolution on your monitor suggest 1768x992 and then restart your computer.
Then open the IDE and see if it helps.
PROBLEM SOLVED ! 
I've been to C:\Users{YourName}\AppData\Local\Arduino15 to find the "preferences.txt" file.
I removed it, and opened Arduino again : a new "preferences.txt" file (shorter) appeared.
/!\ It will remove your recent open files and things like that...
It must be a line in the old "preferences.txt" file that makes the problem.
If someone is interrested, here is the 2 versions of the file : the one that makes it bug and the new one.
Anyway, thank you ballscrewbob and everybody for the Help !!
Cheer's,
Simon
preferences_not_showing_monitor.txt (8.73 KB)
preferences.txt (2.71 KB)
I had the same issue here, and instead of deleting the preferences.txt file, I just closed out the IDE, and deleted the line that read:
last.serial.location=xxxx (where xxx was a series of 4 values)
Once I restarted the IDE, the monitor was visible again.
I had the same issue too, it was due to new monitor. It seemed that the Serial monitor was opening somewhere out of screen.
Solution: Right click it and maximaze it.