Arduinon Nano Access denied

Official Hardware Nano Family Classic Nano
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So i have been tryin gto upload a sketch to my nano and the access is denied every time . Ive tried restarting pc , im sure its on the right port ,ive stopped all proccesses blocking the access and no other IDE instances are open and it still wont let me upload Please help Me

2

What OS?

3

i didnt see but i had the serial monitor open

4

Ok, lets start over:

What OS is your PC running?
What Arduino IDE?

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5

If the selected COM port is right, it might be a processor error. Try selecting Atmega328P (Old Bootloader) and try uploading again.

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Just got a Nano classic (based on the ATMEGA328P), after using the UNO R3, wanted to try something smaller like the Nano. I have searched through the forums, I hope this is the right area. I've tried even the simplest coding, but I only get "avrdude: ser_open(): can't open device "\.\COM4": Access is denied." I've updated my board manager, checked the COM port, I can't get this thing to work. It's powered, the "L" LED is blinking slowly, and when I upload to it, it does a short series of rapid blinks, but that is it. I've been working at this thing for three days now, can anyone please help?

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Hi @raven151. There is a known bug in Arduino IDE 2.x that can cause uploads to fail with this "Access is denied" error if you try uploading to a board using an FTDI FT232R USB chip (as is present on the official classic Nano and its faithful clones) while the Arduino IDE Serial Monitor or Serial Plotter is open.

A port can only be used by one process at a time, so Arduino IDE must automatically close the port in Serial Monitor and Serial Plotter during an upload, automatically opening it again after. For some reason, that juggling of the port control is not working with boards that have the FTDI USB chip.

If that bug is the cause of the problem you are having, the workaround will be to manually close the port in Serial Monitor/Serial Plotter before doing an upload. Please give that a try and then let me know if you still have the error while uploading:

Serial Monitor

  1. Click the X icon on the "Serial Monitor" tab in the bottom panel of the Arduino IDE window to close the tab:
    image
  2. Upload the sketch.
  3. Open Serial Monitor again if needed (by clicking the icon on the IDE toolbar or the Tools > Serial Monitor menu item) after the upload is finished.

Serial Plotter

If you have the "Serial Plotter" window open, the procedure is a bit different from closing the Serial Monitor connection:

  1. Close the "Serial Plotter" window.
  2. If the "Serial Monitor" view is not already open, select Tools > Serial Monitor from the Arduino IDE menus to open it.
    ⓘ We must do an open/close cycle on Serial Monitor as a workaround for a bug in Serial Plotter
  3. Click the X icon on the "Serial Monitor" tab in the bottom panel of the Arduino IDE window to close the tab:
    image
  4. Upload the sketch.
  5. Open Serial Monitor and/or Serial Plotter again if needed after the upload is finished.

Please let me know if you have any questions or problems while following those instructions.

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You're kidding me, right? Three days of trouble shooting, and the serial monitor being open is the trouble?!? ... Yeah. The serial monitor being open is the problem. If I swung that way, I'd offer to kiss you. It's working, I feel really foolish waiting so long to post my problem. How did I miss this in all my searching? Why isn't this included in the little pamphlet included in the box?!?!?! I've been pulling my hair out...never mind. Thank you so very much, it's working, and I'm on my way. Thank you again!

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Just so you know, yeah, it worked. See my other comment!

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You are welcome. I'm glad it is working now.

Regards,
Per

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Because it's not supposed to be like that. The IDE should close the port used by the serial monitor so the IDE can start the upload process on that port. After the upload, the IDE will open the port again in serial monitor (if it was open).

This works flawlessly in IDE 1.x but IDE 2.x does not always manage to close the port. For a variety of boards I can happily upload for hours and all of a sudden it will fail.

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Yeah, I get that. I was just venting comedically, after spending three days trying to update libraries, interfaces, switching comms, updating drivers, on and on. And to have it be something so simple..."click the 'x' and close the serial monitor", I had to throw a mild mannered tantrum and put blame somewhere else, if even for only a moment :smile:.

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