When I compile/verify my sketch I normally get a port "switch". The verbose is like this Upload started Programming with: Serial Restarting in bootloader mode Flashing with command:C:/Users/username/.arduino-create/arduino/bossac/1.7.0-arduino3/bossac.exe -i -d --port=COM7 -U true -i -e -w -v C:/Users/username/AppData/Local/Temp/arduino-create-agent729615173/sketch_Activity_09_apr05a.bin -R ....... (Deleted verbose here) Verify successful done in 0.160 seconds CPU reset. readWord(addr=0)=0x20007ffc readWord(addr=0xe000ed00)=0x410cc601 readWord(addr=0x41002018)=0x10010305 writeWord(addr=0xe000ed0c,value=0x5fa0004) sketch_Activity_09_apr05a uploaded successfully on board Arduino MKR WiFi 1010 (COM9) So, it starts at port=COM7 and ends at port=COM9. Why is that?? Thanks. AA

Perfectly normal and explained in a few posts for the MKR family. https://forum.arduino.cc/search?q=mkr%20changes%20port

Hmm it appears that something killed some of the specific "how to's" They were at the top of almost every section ! [image] Why are the MKR series USB ports so unreliable? MKRWIFI1010 The MKR and a few other boards have DUAL COM ports. One is the regular one and the other is the BOOTLOADER. During programming it would be normal to see it swap those ports then swap back. Quickly double pressing the reset button will hold it in the BOOTLOADER mode which is useful in case your sketch is not quite perfect. Putting a general list below some of which may be useful now or in the near future. Note the USB and Antivirus one. Please take a few moments to Learn and Use The Forum H… Hope that helps.

Thanks. Switching ports is not great concern, but I'm having the board resetting itself periodically. This is what puzzles me, and am wondering if both are related??

There have been different reports and different answers for seemingly random changes. Most common culprit has usually been power saving facilities offered by computers. Other include conflicting usage of the com ports from different software. Anti Virus or similar but more so where an IDE is concerned and during uploads. Bad / Intermittent USB cables. Suggest a search using the forums own search so you can get an idea of the different fixes and see if they apply.

Port keeps changing

Official Hardware MKR Family MKR WiFi 1010

Ballscrewbob April 5, 2023, 6:13pm 4

Hmm it appears that something killed some of the specific "how to's"
They were at the top of almost every section !

Hope that helps.

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Port keeps changing

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