user76341: Each time I attempt to upload to the MKR WiFi 1010 board the COM-port gets disconnected, usually at one of the following points:

Either it disconnects just after compiling/verifying. In this case the LED_BUILTIN pulsates slowly, and the USB-cable needs to be reconnected in order to try again. The next attempt usually results in 2..

Or, it disconnects after a successful upload. The next attempt to upload will always result in 1. occurring. When this happens the COM-port is still visible in Windows Device Manager but it can't be found by a Serial Monitor.


Any ideas what could be causing this or what could be done to have it stay connected? With an UNO this doesn't happen.

user76341: This was due to using a virtual machine (VMware) which apparently doesn't handle the MKR board COM-port so well. Moving the development environment to the host solved the problem. It still disconnects the COM-port after upload but then consistently reconnects to the same COM-port and that's good enough.

76341: <p>Each time I attempt to upload to the <em>MKR WiFi 1010</em> board the COM-port gets disconnected, usually at one of the following points:</p>
<ol>
<li><p>Either it disconnects just after compiling/verifying. In this case the <code>LED_BUILTIN</code> pulsates slowly, and the USB-cable needs to be reconnected in order to try again. The next attempt usually results in <code>2.</code>.</p>
</li>
<li><p>Or, it disconnects after a successful upload. The next attempt to upload will always result in <code>1.</code> occurring. When this happens the COM-port is still visible in Windows Device Manager but it can't be found by a Serial Monitor.</p>
</li>
</ol>
<p>Any ideas what could be causing this or what could be done to have it stay connected? With an <em>UNO</em> this doesn't happen.</p>
 76341: <p>This was due to using a virtual machine (VMware) which apparently doesn't handle the MKR board COM-port so well. Moving the development environment to the host solved the problem. It still disconnects the COM-port after upload but then consistently reconnects to the same COM-port and that's good enough.</p>
