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This error indicates you need to take some drastic action. Be aware this is somewhat advanced and will remove any boards you have installed via Boards Manager:
In the Arduino IDE, click the link on the line following File > Preferences > More preferences can be edited directly in the file. This will open the Arduino15 (or similar name depending on OS) folder.
Delete all files and folders under the Arduino15 folder except for preferences.txt. Please be very careful when deleting things from your computer. When in doubt, back up!
Restart the Arduino IDE
Verify that you can now use your board before reinstalling any packages via Boards Manager.
pert:
This error indicates you need to take some drastic action. Be aware this is somewhat advanced and will remove any boards you have installed via Boards Manager:
In the Arduino IDE, click the link on the line following File > Preferences > More preferences can be edited directly in the file. This will open the Arduino15 (or similar name depending on OS) folder.
Delete all files and folders under the Arduino15 folder except for preferences.txt. Please be very careful when deleting things from your computer. When in doubt, back up!
Restart the Arduino IDE
Verify that you can now use your board before reinstalling any packages via Boards Manager.
I'm glad to hear it worked! The problem was something to do with the update of Arduino AVR Boards you installed via Boards Manager. I don't know exactly what went wrong. There is a possibility it will happen again when you update Arduino AVR Boards again, but I don't think that will happen.
I find it is not File>Preferences.... but Arduino>Preferences...
But to further clarify, can all of the "libraries" stuff under Arduino15 be moved to wherever I have my user Arduino stuff or does some stuff simply have to stay in the hidden Library file. I use Mac.
sevenoutpinball:
I find it is not File>Preferences.... but Arduino>Preferences...
File > Preferences is the menu path on Windows and Linux. I don't own a Mac and have only used macOS a few times in my life so I'm not very knowledgeable about that OS. I'll try to remember this for the future so that my instructions will apply to all operating systems.
sevenoutpinball:
can all of the "libraries" stuff under Arduino15 be moved to wherever I have my user Arduino stuff or does some stuff simply have to stay in the hidden Library file.
It all must stay at /Users/{username}/Library/Arduino15
The only possible other option would be to run the Arduino IDE in portable mode, in which case those files would be stored under the portable folder of the Arduino IDE subfolder. Unfortunately, it is either difficult or impossible to run the Arduino IDE in portable mode on macOS. More information here: http://forum.arduino.cc/index.php?topic=539551.msg3678998#msg3678998
I would like to have all the library files in ONE place. Somehow I wind up with too many directories for this stuff and one place would be great. Mac keeps the Arduino15 stuff in a hidden place and that makes it a hassle to deal with.
Theoretically, you can install the hardware cores in the hardware subfolder of your sketchbook. The reality is this can be quite difficult to do with some of the hardware cores, due to the need to install their toolchain in just the right place. I think it's more trouble than it's worth.
I get the same issue all the time. It seems that going from one board to another does this mostly. If you set it to Uno and just compile the blink it should work. Anything else is going to be a problem of incompatible library with your board.
sevenoutpinball:
If you set it to Uno and just compile the blink it should work. Anything else is going to be a problem of incompatible library with your board.
That's a huge exaggeration. There are as many, if not more, architecture-independent libraries as there are architecture-specific libraries. The Arduino framework has been designed with portability in mind.
And having all the libraries under one folder won't help at all with that.
If you're having a specific problem, create a new topic about it and we'll help you out.
I've run into issues where say multiple GitHub things use the same device but with different functions maybe but all using the nomenclature say <TEA5767.h>. So you get weird things in compile and if you are not used to that it is a hassle.