# Setup running twice **URL:** \ **Category:** Programming\ **Created:** [July 12, 2026, 6:31am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712 "2026-07-12T06:31:46Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![gilshultz](https://avatars.discourse-cdn.com/v4/letter/g/67e7ee/32.png) [@gilshultz](https://forum.arduino.cc/u/gilshultz)\ **Post date:** [July 12, 2026, 4:40pm UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/21 "2026-07-12T16:40:46Z")
The UNO, Nano, and several other Arduino boards will often reset when the serial port is opened. Depending on the board, IDE, and operating system, you may see one or even two resets. This behavior is related to the auto-reset circuitry and the USB interface. My usual solution is to add a two-second delay immediately after `Serial.begin()`, which is typically the first line in `setup()`. In most cases, this allows the reset sequence to complete before the rest of the program starts. Some users disable or modify the auto-reset circuit, often by adding a capacitor, but I generally just let the board reset. The two-second delay also makes it easier to recover if I accidentally flood the serial port with output. ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [July 12, 2026, 4:49pm UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/22 "2026-07-12T16:49:22Z")
Linux Mint 22.3 Arduino IDE 2.3.8 Arduino Uno clone Serial Monitor already open, time stamps on. After uploading I see this. It does print almost twice! ![image](https://europe1.discourse-cdn.com/arduino/original/4X/0/9/e/09e2acae1196c75cb1efdbda0433f96ba02239d8.png) Looks like an IDE bug. ---
**Author:** ![sterretje](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/sterretje/32/391294_2.png) [@sterretje](https://forum.arduino.cc/u/sterretje)\ **Post date:** [July 13, 2026, 1:28am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/23 "2026-07-13T01:28:29Z")
> [@jim-p](#): > > Looks like an IDE bug. That must be a very old bug 😉 I did test the setup with IDE 1.8.19 on Manjaro Linux and had the same result as pommie. Testing under Windows 11 I get the expected result for a (clone) Nano and I get a row of blocks first when using an original Mega. ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [July 13, 2026, 9:34am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/24 "2026-07-13T09:34:21Z")
> [@sterretje](#): > > That must be a very old bug Seems so. I think over the years I have learned to just ignore it and forgot it was even there. Did not seem like it was worth spending time on trying to debug. ---
**Author:** ![gilshultz](https://avatars.discourse-cdn.com/v4/letter/g/67e7ee/32.png) [@gilshultz](https://forum.arduino.cc/u/gilshultz)\ **Post date:** [July 13, 2026, 5:46pm UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/25 "2026-07-13T17:46:45Z")
One side effect is that opening the Serial Monitor may also reset the board. In my experience, this is not always true. Generally, the behavior is not caused by the IDE sending a special reset command. It is the result of opening the serial port and toggling DTR, which may also cause the computer to re-enumerate the USB device, sometimes resulting in a different port assignment. The capacitor modification holds the reset line in a state that prevents the auto-reset pulse, so the host does not see the disconnect/reconnect sequence that triggers re-enumeration. I have observed this behavior since Arduino IDE 1.0, around 2012, when I was using Linux Mint 12 Lisa with the Cinnamon 1.2 desktop. ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [July 15, 2026, 10:25am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/26 "2026-07-15T10:25:43Z")
So it's an IDE bug that resets the board twice. ---
**Author:** ![gcjr](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/gcjr/32/314015_2.png) [@gcjr](https://forum.arduino.cc/u/gcjr)\ **Post date:** [July 15, 2026, 11:06am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/27 "2026-07-15T11:06:31Z")
the link i posted said on some boards the serial interface DTR (data terminal ready) pin causes a reset. There's not specific command from the IDE to reset the board. there may be ways over a serial USB interface for a laptop to control individual serial interface pins, but it seems odd that it would do something \> half sec after connecting to the board to reset it. [![image](https://europe1.discourse-cdn.com/arduino/original/4X/d/2/8/d28bd4f3840490bf9b5fc4a5169836d0e91889d1.jpeg)](https://stratusengineering.com/rs232-9-pin-pinout/) ---
**Author:** ![pommie](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@pommie](https://forum.arduino.cc/u/pommie)\ **Post date:** [July 21, 2026, 6:53am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/28 "2026-07-21T06:53:56Z")
My apologies for not replying earlier, I had a computer problem. However, it looks like things have progressed (on here) and maybe my problem isn't just me. I'm currently installing the latest version of mint and will let you know if that fixes anything. It's a slow process. Time to reboot, wish me luck. ---
**Author:** ![pommie](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@pommie](https://forum.arduino.cc/u/pommie)\ **Post date:** [July 21, 2026, 6:58am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/29 "2026-07-21T06:58:42Z")
Seems to have worked alright, just running update/upgrade and will report back later. ---
**Author:** ![pommie](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@pommie](https://forum.arduino.cc/u/pommie)\ **Post date:** [July 21, 2026, 7:12am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/30 "2026-07-21T07:12:41Z")
It appears to be fine however I now have a different problem I've downloaded the file arduino-ide\_2.3.10\_Linux\_64bit.AppImage and run it but I don't have an item under the menu that is programming and the only way to get the program back is by running the AppImage file again. Is this an Arduino or Linux bug or me? ---
**Author:** ![pommie](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@pommie](https://forum.arduino.cc/u/pommie)\ **Post date:** [July 21, 2026, 7:18am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/31 "2026-07-21T07:18:29Z")
Downloaded from [https://www.arduino.cc/en/software/](https://www.arduino.cc/en/software/) ---
**Author:** ![pommie](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@pommie](https://forum.arduino.cc/u/pommie)\ **Post date:** [July 21, 2026, 8:35am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/32 "2026-07-21T08:35:08Z")
It's different because all the other threads are closed and not postable(is that a word) to. ---
**Author:** ![pommie](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@pommie](https://forum.arduino.cc/u/pommie)\ **Post date:** [July 21, 2026, 8:39am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/33 "2026-07-21T08:39:22Z")
> [@van\_der\_decken](#): > > How is it different? I was replying to this post in my previous post. ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [July 21, 2026, 9:30am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/34 "2026-07-21T09:30:15Z")
> [@pommie](#): > > or me? It's you. That is how appimages work. I just moved mine to the desktop and launch it from there. ---
**Author:** ![pommie](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@pommie](https://forum.arduino.cc/u/pommie)\ **Post date:** [July 21, 2026, 9:33am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/35 "2026-07-21T09:33:51Z")
You need to explain that more. I moved the file to the desktop and ran it there with the same result. Help. ---
**Author:** ![pommie](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@pommie](https://forum.arduino.cc/u/pommie)\ **Post date:** [July 21, 2026, 9:37am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/36 "2026-07-21T09:37:07Z")
Is there a difference between running and launching? If so, how do I launch? ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [July 21, 2026, 9:42am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/37 "2026-07-21T09:42:34Z")
> [@pommie](#): > > Is there a difference between running and launching? Don't know. I guess I could have said run. Not a linux expert. So you no longer have the setup running twice problem? ---
**Author:** ![pommie](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@pommie](https://forum.arduino.cc/u/pommie)\ **Post date:** [July 21, 2026, 10:00am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/38 "2026-07-21T10:00:29Z")
[quote="jim-p, post:37, topic:1451712"] So you no longer have the setup running twice problem? [/quote]I don't know as i can't install it. ---
**Author:** ![pommie](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@pommie](https://forum.arduino.cc/u/pommie)\ **Post date:** [July 21, 2026, 10:06am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/39 "2026-07-21T10:06:15Z")
Think I'll try vscode as that appears to be an alternative path as I appear to have reached a dead end here. ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [July 21, 2026, 10:06am UTC](https://forum.arduino.cc/t/setup-running-twice/1451712/40 "2026-07-21T10:06:28Z")
I followed these instructions [https://docs.arduino.cc/software/ide-v2/tutorials/getting-started/ide-v2-downloading-and-installing/](https://docs.arduino.cc/software/ide-v2/tutorials/getting-started/ide-v2-downloading-and-installing/) Had no problems. [Previous page](https://forum.arduino.cc/t/setup-running-twice/1451712.md?page=1) [Next page](https://forum.arduino.cc/t/setup-running-twice/1451712.md?page=3)