isextract (extract v3 InstallShield files) isextract is a command line tool to extract the *.z InstallShield v3 packages many old windows games were distributed as. The files isextract supports are identified by the file command as "InstallShield Z archive Data", and begin with a hex signature of 13 5d 65 8c 3a 01 02. See also: unshield, for other types of InstallShield files.