# MKR1000 creates new COM ports upon upload/reset **URL:** \ **Category:** MKR 1000 WiFi\ **Created:** [April 18, 2016, 2:19pm UTC](https://forum.arduino.cc/t/mkr1000-creates-new-com-ports-upon-upload-reset/380469 "2016-04-18T14:19:46Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![bcraigie](https://avatars.discourse-cdn.com/v4/letter/b/f9ae1b/32.png) [@bcraigie](https://forum.arduino.cc/u/bcraigie)\ **Post date:** [April 18, 2016, 2:19pm UTC](https://forum.arduino.cc/t/mkr1000-creates-new-com-ports-upon-upload-reset/380469/1 "2016-04-18T14:19:46Z")
Interesting... In Windows 10, this is the scenario: MKR1000 is plugged in to a USB port on my Windows 10 laptop. I then go in to Arduino (1.6.8 or latest nightly build for today) and I can see the MKR1000 at COM8. OK so far... Then I load up a bit of code and publish it to the Arduino. It sometimes fails (com port busy, or can't set mask) but when it doesn't fail, it will upload the code to the Arduino which then does the reset CPU... and windows finds it again at COM9. Hmm... So, I change Arduino IDE to use COM9 so that I can start up the serial monitor. So far it is ok. Now, if I update my script and publish it again, upon reset, Windows finds the Arduino at COM10 ! It then goes back to COM8 if I publish again. In all this, I have not unplugged the USB cable. Also, if I press the reset button on the MKR1000, Windows 10 again changes the COM port. This problem with changing COM ports does not happen with other models of Arduino, just with the MKR1000. I'm in the UK, so it is a Genuino MKR1000 that I have (if it makes any difference). So... it seems there is a problem with the MKR1000 USB driver for Windows 10. Anyone else seeing this? ---
**Author:** ![pert](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/pert/32/217111_2.png) [@pert](https://forum.arduino.cc/u/pert)\ **Post date:** [April 18, 2016, 3:05pm UTC](https://forum.arduino.cc/t/mkr1000-creates-new-com-ports-upon-upload-reset/380469/2 "2016-04-18T15:05:04Z")
This might be helpful to you: [arduino micro upload program easier - Installation & Troubleshooting - Arduino Forum](http://forum.arduino.cc/index.php?topic=393530) ---
**Author:** ![TomArd](https://avatars.discourse-cdn.com/v4/letter/t/e495f1/32.png) [@TomArd](https://forum.arduino.cc/u/TomArd)\ **Post date:** [January 8, 2019, 8:59pm UTC](https://forum.arduino.cc/t/mkr1000-creates-new-com-ports-upon-upload-reset/380469/3 "2019-01-08T20:59:33Z")
I have same problem but using the MKR1010Wifi, Update to latest Software 1.8.8. I try 3 diferente Arduino and same problem Someone can help me? Sketch uses 10952 bytes (4%) of program storage space. Maximum is 262144 bytes. Atmel SMART device 0x10010005 found Device : ATSAMD21G18A Chip ID : 10010005 Version : v2.0 [Arduino:XYZ] Mar 19 2018 09:45:14 Address : 8192 Pages : 3968 Page Size : 64 bytes Total Size : 248KB Planes : 1 Lock Regions : 16 Locked : none Security : false Boot Flash : true BOD : false BOR : false Arduino : FAST\_CHIP\_ERASE Arduino : FAST\_MULTI\_PAGE\_WRITE Arduino : CAN\_CHECKSUM\_MEMORY\_BUFFER Erase flash done in 0.834 seconds Write 11224 bytes to flash (176 pages) SAM-BA operation failed An error occurred while uploading the sketch [==========] 36% (64/176 pages) [=====================] 72% (128/176 pages) [==============================] 100% (176/176 pages) done in 0.076 seconds Verify 11224 bytes of flash with checksum. Verify successful done in 0.015 seconds CPU reset. ---
**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:** [May 7, 2021, 11:51am UTC](https://forum.arduino.cc/t/mkr1000-creates-new-com-ports-upon-upload-reset/380469/4 "2021-05-07T11:51:25Z")
Closed on May 7, 2021, 11:51am UTC