update 1.6.21 does not work with nano

Development Tools Uploading
1

Uploading sketches suddenly was not possible anymore. Cable, computer, board, software, IDE ,port , computer: everything was checked. Last thing I thought of: the board manager

The update for Arduino AVR board in board manager 1.6.21 does not work. It gives a time out on my MacBook. I switched back to 1.6.20 and it works again. Please be aware of this!

Hope this saves you time

2

There's no need to revert to Arduino AVR Boards 1.6.20. You only need to select Tools > Processor > ATmega328P (Old Bootloader).

3

Thanks! I did try this solution yesterday, but I got an error message (upload error). Because of your advice I tried a few times more today and now it works, thanks!