This is a very helpful option in the following situations:
oYou lost your Code Definition file(s), but still have at least one data file with coded data.
oYou started collecting your observations in an explorative way and want to use (part of) the expressions you used for your coding system.
Whenever you have one or more data files, INTERACT automatically creates a compilation of all Class Code combinations in the background. This information is stored in a Code Archive file.
▪Open a data file that contains the data you want to use in your Code Definitions.
▪Open the Timeline Chart to make sure the corresponding Code Archive is available on your system.
▪Click Start - Observation - Define Codes 
to open the Code Definition dialog.
▪If required, click New to create a new empty Code Definition file.
▪Click on the Code Archive icon inside the Current Codes dialog.
▪Select the Codes you want to use from the upcoming Code Archive preview dialog:
▪Confirm your selection with OK.
▪Add or adjust further Codes you your Code Definition file and save it like you would any other Code Definition file.