user15959: After months of good use, both my boards Mega 2560 and Uno became unavailable for uploading sketch or burning bootloader.
Sketch uses 444 bytes (1%) of program storage space. Maximum is 32256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes.
C:\[...]bin/avrdude -CC:[...]avrdude\6.3.0-arduino9/etc/avrdude.conf -v -patmega328p -cstk500v1 -PCOM5 -Uflash:w:C:\Users\GREGOR~1\AppData\Local\Temp\arduino_build_242793/BareMinimum.ino.hex:i 

avrdude: Version 6.3, compiled on Jan 17 2017 at 12:00:53
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "C:[...]\arduino\tools\avrdude\6.3.0-arduino9/etc/avrdude.conf"

         Using Port                    : COM5
         Using Programmer              : stk500v1
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x03

Facts :

v1.6.20 of the boards
v1.8.5 of the IDE
Windows 8.1 64bits
Programmer: "AVR ISP"
Drivers are fine (the boards are well recognized)
Serial monitor works
I'm trying to upload the "Bare minimum" exemple sketch
Nothing in pin 0 and 1, nothing at all is plugged actually
Get Board info:
Uno : VID 2A03
Mega2560 : VID 2A03
From instructions here, every instruction is "echoed back"

What i tried :

https://forum.arduino.cc/index.php?topic=385160.0
avrdude: stk500_recv(): programmer is not responding
https://zestedesavoir.com/forums/sujet/5676/probleme-televersement-arduino
All other programmers
A few old versions of boards
Resetting the boards a few times, during upload, before, after...

Nothing works. If you have any idea.....
Thank you all !

user15959: It eventually worked by using upload / ctrl+U (what I didn't try... smh) instead of  upload using programmer / ctrl+shift+U.
So i know now where it comes from, though I don't know what's wrong with AVR ISP.

15959: <p>After months of good use, both my boards Mega 2560 and Uno became unavailable for uploading sketch or burning bootloader.</p>

<pre><code>Sketch uses 444 bytes (1%) of program storage space. Maximum is 32256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes.
C:\[...]bin/avrdude -CC:[...]avrdude\6.3.0-arduino9/etc/avrdude.conf -v -patmega328p -cstk500v1 -PCOM5 -Uflash:w:C:\Users\GREGOR~1\AppData\Local\Temp\arduino_build_242793/BareMinimum.ino.hex:i 

avrdude: Version 6.3, compiled on Jan 17 2017 at 12:00:53
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "C:[...]\arduino\tools\avrdude\6.3.0-arduino9/etc/avrdude.conf"

         Using Port                    : COM5
         Using Programmer              : stk500v1
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x03
</code></pre>

<p><strong>Facts :</strong></p>

<ul>
<li>v1.6.20 of the boards</li>
<li>v1.8.5 of the IDE</li>
<li>Windows 8.1 64bits</li>
<li>Programmer: "AVR ISP"</li>
<li>Drivers are fine (the boards are well recognized)</li>
<li>Serial monitor works</li>
<li>I'm trying to upload the "Bare minimum" exemple sketch</li>
<li>Nothing in pin 0 and 1, nothing at all is plugged actually</li>
<li>Get Board info:</li>
<li>Uno : VID 2A03</li>
<li>Mega2560 : VID 2A03</li>
<li>From instructions <a href="https://arduino.stackexchange.com/questions/13292/have-i-bricked-my-arduino-uno-problems-with-uploading-to-board">here</a>, every instruction is "echoed back"</li>
</ul>

<p><strong>What i tried :</strong></p>

<ul>
<li><a href="https://forum.arduino.cc/index.php?topic=385160.0" rel="nofollow noreferrer">https://forum.arduino.cc/index.php?topic=385160.0</a></li>
<li><a href="https://arduino.stackexchange.com/questions/22191/avrdude-stk500-recv-programmer-is-not-responding">avrdude: stk500_recv(): programmer is not responding</a></li>
<li><a href="https://zestedesavoir.com/forums/sujet/5676/probleme-televersement-arduino" rel="nofollow noreferrer">https://zestedesavoir.com/forums/sujet/5676/probleme-televersement-arduino</a></li>
<li>All other programmers</li>
<li>A few old versions of boards</li>
<li>Resetting the boards a few times, during upload, before, after...</li>
</ul>

<p>Nothing works. If you have any idea.....</p>

<p>Thank you all !</p>
 15959: <p>It eventually worked by using <strong>upload</strong> / ctrl+U (what I <em>didn't try</em>... smh) instead of  <strong>upload using programmer</strong> / ctrl+shift+U.</p>

<p>So i know now where it comes from, though I don't know what's wrong with AVR ISP.</p>
