I keep a 1st generation AppleTV in my RV because it stores lots of movies on its hard drive, so I can watch without internet. It's been a couple years since I attempted to connect it to iTunes to update the movies that are on it, but I notice that it no longer appears as a device in iTunes 12 on High Sierra (on the same computer/library it used to connect to.) It's connected to the same WiFi network just fine, it can connect to internet services no problem. But I can't sync movies to it.
I see one reply to a thread from a year ago that says that doing a factory restore made it reappear in iTunes 12, but I'm hoping someone else has confirmation that fixes it - I don't want do to a factory restore and erase all the stored movies only to not be able to reload them! (They're all in the iTunes library, so if I know I can re-sync, it's not a problem. I just don't want to turn it in to a brick waiting for an iTunes that will never connect.)
Of note - iTunes does still let you download SD copies of current purchases, even downloading the ancient 320x240 "low-quality SD" videos compatible with the first-generation iPod Video! Although the low-quality SD versions aren't much smaller than the high-quality SD versions. (Blade Runner 2049 - 2.61 vs 2.81 GB! And 6.62 GB for the 1080p.) Yes, I put the low-quality SD versions on the AppleTV, because the TV in the RV is crap, and you can't tell the difference. I can fit more movies that way.
I see one reply to a thread from a year ago that says that doing a factory restore made it reappear in iTunes 12, but I'm hoping someone else has confirmation that fixes it - I don't want do to a factory restore and erase all the stored movies only to not be able to reload them! (They're all in the iTunes library, so if I know I can re-sync, it's not a problem. I just don't want to turn it in to a brick waiting for an iTunes that will never connect.)
Of note - iTunes does still let you download SD copies of current purchases, even downloading the ancient 320x240 "low-quality SD" videos compatible with the first-generation iPod Video! Although the low-quality SD versions aren't much smaller than the high-quality SD versions. (Blade Runner 2049 - 2.61 vs 2.81 GB! And 6.62 GB for the 1080p.) Yes, I put the low-quality SD versions on the AppleTV, because the TV in the RV is crap, and you can't tell the difference. I can fit more movies that way.