fructose writes: "The Nest Protect has a flaw in its software that, under the right circumstances, could disable the alarm and not notify the owners of a fire. To remedy this flaw, they are disabling the Nest Wave feature through automatic updates. Owners who don't have their Nest Protects connected to their WiFi net or don't have a Nest account are suggested to either update the device manually or return it to Nest for a full refund. While they work out the problem, all sales are being halted to prevent unsafe units from being sold. There have been no reported incidents resulting from this flaw, but they aren't taking any chances."