I’ve had looping on both SU4 and SU5 now, and discovered this technique independently before finding this link. It does work. Not sure if it will work for you, but after 2x of looping on the Caravan, I paused both times, Red-X’d cleanly out of the installer and restarted the sim. First reconnect returned connection errors (mind you I was two hours out of the SU5 release, effectively “rush hour”), and then the second attempt successfully pulled down the looping files. It actually acknowledged I had pulled down about 50 percent already of the 36GB update (I don’t install everything, hence mine is typically smaller than the reported average size), then showed me accurate size remaining. It finished - slowly, but it did finish.
Install Looping Helped By Pausing, then Resuming, The Install Process