# Problems uploading a program into Pro Mini the 2nd time **URL:** \ **Category:** Uploading\ **Created:** [March 6, 2022, 5:04am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273 "2022-03-06T05:04:32Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Rod\_Arduino\_user](https://avatars.discourse-cdn.com/v4/letter/r/13edae/32.png) [@Rod\_Arduino\_user](https://forum.arduino.cc/u/Rod_Arduino_user)\ **Post date:** [March 6, 2022, 5:04am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/1 "2022-03-06T05:04:32Z")
Hi, I can upload a sketch and program a Arduino Pro Mini ok once only. What is loaded works OK. But I can't upload another sketch to program it again. That is to reprogram it. It keeps running the old program Sketch. Thanks, ---
**Author:** ![in0](https://avatars.discourse-cdn.com/v4/letter/i/77aa72/32.png) [@in0](https://forum.arduino.cc/u/in0)\ **Post date:** [March 6, 2022, 6:11am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/2 "2022-03-06T06:11:32Z")
> [@Rod\_Arduino\_user](#): > > I can't upload another sketch to program it again Please provide a detailed description of what you mean by "I can't upload". Include the full and exact text of any error or warning messages that might be associated with the problem. ---
**Author:** ![westfw](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/westfw/32/213443_2.png) [@westfw](https://forum.arduino.cc/u/westfw)\ **Post date:** [March 6, 2022, 6:23am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/3 "2022-03-06T06:23:39Z")
"upload works once after installing bootloader" is usually due to a non-functioning auto-reset circuit. ---
**Author:** ![Rod\_Arduino\_user](https://avatars.discourse-cdn.com/v4/letter/r/13edae/32.png) [@Rod\_Arduino\_user](https://forum.arduino.cc/u/Rod_Arduino_user)\ **Post date:** [March 9, 2022, 11:52am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/4 "2022-03-09T11:52:52Z")
Hi, A sketch was uploaded to a Pro Mini that works ok. Then on doing another upload to it. I get the following error message: Arduino: 1.8.19 (Windows Store 1.8.57.0) (Windows 10), Board: "Arduino Pro or Pro Mini, ATmega168 (5V, 16 MHz)" Sketch uses 6896 bytes (48%) of program storage space. Maximum is 14336 bytes. Global variables use 423 bytes (41%) of dynamic memory, leaving 601 bytes for local variables. Maximum is 1024 bytes. avrdude: ser\_open(): can't open device "\.\COM4": The system cannot find the file specified. Thanks for your help. Problem uploading to board. See [https://support.arduino.cc/hc/en-us/sections/360003198300](https://support.arduino.cc/hc/en-us/sections/360003198300) for suggestions. This report would have more information with "Show verbose output during compilation" option enabled in File -\> Preferences. ---
**Author:** ![Rod\_Arduino\_user](https://avatars.discourse-cdn.com/v4/letter/r/13edae/32.png) [@Rod\_Arduino\_user](https://forum.arduino.cc/u/Rod_Arduino_user)\ **Post date:** [March 9, 2022, 11:59am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/5 "2022-03-09T11:59:30Z")
Hi, I have not installed a Bootloader. Is that what I should do? It was a new (never used) Pro Mini that will upload a sketch once. But not the second time. All 3 new Pro Mini chips do the same thing. Thanks. ---
**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:** [March 9, 2022, 12:06pm UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/6 "2022-03-09T12:06:06Z")
If you could upload the first time via a TTL-to-USB converter, the ProMini has a boot loader. If you uploaded the first time via ICSP (via a programmer), the boot loader is wiped and an normal upload via using the TTL-to-USB converter is no longer possible. > [@Rod\_Arduino\_user](#): > > avrdude: ser\_open(): can't open device ".\COM4": The system cannot find the file specified. What does Windowsd device manager think of your board when that happens. Be aware that Windows is free to assign whichever port number it wants to assign. ---
**Author:** ![Rod\_Arduino\_user](https://avatars.discourse-cdn.com/v4/letter/r/13edae/32.png) [@Rod\_Arduino\_user](https://forum.arduino.cc/u/Rod_Arduino_user)\ **Post date:** [March 14, 2022, 10:48am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/7 "2022-03-14T10:48:53Z")
Hi, Thanks for your help. Are you able to burn the Bootloader after it has been removed? Thanks, ---
**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:** [March 15, 2022, 7:21am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/8 "2022-03-15T07:21:56Z")
Under the _tools_ menu is an option to burn the bootloader. ---
**Author:** ![Rod\_Arduino\_user](https://avatars.discourse-cdn.com/v4/letter/r/13edae/32.png) [@Rod\_Arduino\_user](https://forum.arduino.cc/u/Rod_Arduino_user)\ **Post date:** [March 15, 2022, 11:51pm UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/9 "2022-03-15T23:51:45Z")
Hi, Thanks again for your help. I try that and see if it works, thanks, ---
**Author:** ![anon94801460](https://avatars.discourse-cdn.com/v4/letter/a/278dde/32.png) [@anon94801460](https://forum.arduino.cc/u/anon94801460)\ **Post date:** [March 16, 2022, 12:09am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/10 "2022-03-16T00:09:07Z")
This message has nothing to do with the bootloader. The computer can't find the USB to serial adapter. What are you using for that? > [@Rod\_Arduino\_user](#): > > avrdude: ser\_open(): can't open device ".\COM4": The system cannot find the file specified. ---
**Author:** ![Rod\_Arduino\_user](https://avatars.discourse-cdn.com/v4/letter/r/13edae/32.png) [@Rod\_Arduino\_user](https://forum.arduino.cc/u/Rod_Arduino_user)\ **Post date:** [March 16, 2022, 12:53am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/11 "2022-03-16T00:53:34Z")
Hi, Am I correct that I can not do a Burn Bootloader via the serial USB. And I need to install a Programmer to do that? thanks, ---
**Author:** ![anon94801460](https://avatars.discourse-cdn.com/v4/letter/a/278dde/32.png) [@anon94801460](https://forum.arduino.cc/u/anon94801460)\ **Post date:** [March 16, 2022, 1:42am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/12 "2022-03-16T01:42:53Z")
See reply #10. You can't do anything until your computer recognizes the USB to serial converter. If you have successfully loaded a sketch, then the Arduino Pro Mini has a bootloader. ---
**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\ **Post date:** [September 12, 2022, 1:43am UTC](https://forum.arduino.cc/t/problems-uploading-a-program-into-pro-mini-the-2nd-time/966273/13 "2022-09-12T01:43:22Z")
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