Indeed. The sets were left standing from 1977's Phase II work until they were modified for TNG nearly a decade later. I find this extraordinary - didn't Paramount need the stages for other productions? Perhaps they decided with the continuing Star Trek film series that they'd need to store the sets somewhere.That's not correct. By 1983, the sets on stage 9 had been left standing since TWOK (possibly even TMP, but I haven't found evidence for that). As I've detailed elsewhere on the board, the standing Enterprise sets were reused and redressed heavily in Star Trek III and later IV. Roddenberry's intro to the 1986 release of The Cage, filmed at Stage 9 shows the Engineering set completely intact, though it hadn't been used in the production of TVH at all.