Abstract: A compressor includes an axially split casing surrounding stages of rotor blades and stator vanes. The vanes include a shroud joined to radially inner ends thereof and disposed in a cavity adjoining a rotor disk. An annular cavity seal abuts the vane shroud and adjoins the rotor disk for sealing the cavity therebetween. The seal is axially retained to the shroud in both casing halves, and is radially inwardly retained in only the casing lower half for allowing assembly and removal of the casing upper half relative to the casing lower half without radial interference between the shroud and the seal.