I keep getting " SM Bus Controller is not installed" message for my PC under the " Device and Printers" menu from the Control panel. The System Management Bus ( abbreviated to SMBus or SMB) is a single- ended simple two- wire bus for the purpose of lightweight communication. Note: SMBus is the System Management Bus used in personal computers and servers for low- speed, system management communications. Home » SM Bus Controller Use the links on this page to download the latest version of SM Bus Controller drivers. It means SM Bus Controller Driver is missing. I have a XPS420 and I' ve got the yellow exclamation point next to " SM Bus Controller" in my device manager.Just go with the tried- and- true ways below, you can fix it at once. I have installed the latest chipset drivers for my MB from the Asus driver/ support page.