I have had problems installing the CAN plugin.
Before installing Studio 4.12 I had a previous version and the CAN plugin installed.
When I installed version 4.12.460 of Studio, I uninstalled and cleaned up (at least that was what I thought). But somehow something related to the CAN plugin was still there.
When I tried to install AT90CAN128 Plugin 1.0.5, I got an error saying that the .msi install file could not be found. But it was there, I could see it in file explorer.
The solution was to uninstall the plugin first via the install shield started by setup.exe. I got an eror message saying that the plugin was not installed.
The next attemt to install succeded :-)