Trying to force update_dyld_shared_cache but having some errors

I am trying to force the update of my dyld shared cache using the command sudo update_dyld_shared_cache -root / -force But after a while I see a bunch of errors like this, related to spindump: >update_dyld_shared_cache : Unable to unlink //var/db/spindump/OLDDSC-E2D77243-3FD9-32E5-AE64-3506904D5579: 1 Operation not permitted How do I fix this? I am on El Capitan.