Abbrev. of the derogatory phrase "Chair-to-Keyboard Interface"; Used to clandestinely express that a computer problem was due to user error, or the fault of the user; A common source of computer problems.
Variation: "CKI" (or Chair-Keyboard Interface)
Related term: noob
The tech, after only a few minutes of work, figured out that the computer crashes were caused by the CTKI, and highly recommended replacing that defective part.