A picture is worth a thousand words.
Could you take a few moments to Learn How To Use The ForumHow to get the best out of this forum
Your OS and version can be valuable information, please include it along with extra security you are using.
Always list the version of the IDE you are using and the board version if applicable.
Use quote or add error messages as an attachment NOT a picture.
How to insert an image into your post. ( Thanks @Robin2 )
Add your sketch where applicable but please use CODE TAGS ( </> )
Add a SCHEMATIC were needed even if it is hand drawn
Add working links to any specific hardware as needed (NOT links to similar items)
Remember that the people trying to help cannot see your problem so give as much information as you can
COMMON ISSUES
Ensure you have FULLY inserted the USB cables.
Check you have a COMMON GROUND where required. ( Thanks @Perry )
Where possible use USB 2.0 ports or a USB 2.0 POWERED HUB to rule out USB 3.0 issues.
Try other computers where possible.
Try other USB leads where possible.
You may not have the correct driver installed. CH340/341 or CP2102
There may be a problem with the board check or remove your wiring first.
Remove any items connected to pins 0 and 1.
COMPUTER RELATED
Close any other serial programs before opening the IDE.
Ensure you turn off any additional security / antivirus just to test.
There may be a problem with the PC try RESTARTING it.
You may be selecting the wrong COM port.
Avoid cloud/network based installations where possible OR ensure your Network/Cloud software is RUNNING.
Clear your browsers CACHE.
Close the IDE before using any other serial programs.
Preferably install IDE’s as ADMINISTRATOR or your OS equivalent
ARDUINO SPECIFIC BOARDS
CH340/341 based clones do not report useful information to the “get board info” button.
NANO (Old Types) some require you to use the OLD BOOTLOADER option.
NANO (ALL Types ) See the specific sections lower in the forum.
NANO (NEW Types ) Install your board CORE’s.
Unless using EXTERNAL PROGRAMMERS please leave the IDE selection at default “AVRISP mkII”.
Boards using a MICRO usb connector need a cable that is both DATA and CHARGE. Many are CHARGE ONLY.
CREATE editor install locations.
On macOs ~/Applications/ArduinoCreateAgent-1.1/ArduinoCreateAgent.app/Contents/MacOS/config.ini
On Linux ~/ArduinoCreateAgent-1.1/config.ini
On Windows C:\Users[your user]\AppData\Roaming\ArduinoCreateAgent-1.1
Performing the above actions may help resolve your problem without further help. Language problem ? Try a language closer to your native language:
Thanks to all those who helped and added to this list.