Citing problems with security and accuracy the Secretary Of State has decertified electronic voting machines used throughout the state. From Denver Channel 7:

Colorado’s top election official decertified electronic voting machines used in some of the state’s largest counties on Monday, including Denver, Arapahoe and Jefferson.

The devices are also used in Pueblo, Mesa and Elbert counties.

Secretary of State Mike Coffman cited security or accuracy problems in the decertified machines.

You can also read the report from the Secretary of State’s office .