COSMOS

Unfortunately there is currently a bug in COSMOS which prevents certain properties from being posted. There's no good way to figure out which ones are broken other than to dig through the COSMOS source code. For now you can try using a different property to store your values. Hopefully this issue gets fixed soon!

This seems to be a bug in COSMOS, but it's difficult to replicate. For now you can try switching the order you create your devices. If you have only a single device, you can add another device beforehand which goes unused.

Raspberry Pi

Disconnecting power to the Raspberry Pi without shutting it down beforehand can cause the micro SD card containing the operating system to become corrupted. Unfortunately you probably won't be able to recover any data from the card. If you can't even connect to the Raspberry Pi from a desktop machine or laptop, you should try flashing its micro SD card with a fresh image.

This is an issue caused by the time it takes to establish a SSH connection between the BeagleBone and Raspberry Pi. To fix this, you can try disabling DNS in the SSH configuration for both the BeagleBone and Raspberry Pi.

BeagleBone

Uh oh, that could be bad. Sometimes connecting or disconnecting peripherals while the BeagleBone is powered can damage the internal power lines (we've done this ourselves, unfortunately). If you can't get correct voltages after a while, it could be that your BeagleBone is fried, and you'll need to find a new one.

VirtualBox

It could be because you need to enable hardware virtualization on your motherboard. For most motherboards you'll probably be able to find a guide for this.

You'll need to install VirtualBox Guest Additions on your guest machine.

It might be a problem with hardware acceleration using your GPU. In the settings for the virtual machine you can go to the Display tab and change the graphics controller setting, or disable hardware acceleration.