I noticed my iPhone’s System Data had somehow grown to 25GB, so I did a bit of digging and ended up freeing about 8GB. The first thing that helped was a force restart: press Volume Up, release, press Volume Down, release, then hold the Power button until the Apple logo appears. After the phone rebooted and sat for a minute or two, checking Settings → General → iPhone Storage showed that a few gigabytes were already gone. Next, I toggled iCloud Drive off and back on, which turned out to be surprisingly effective. I went to Settings → Apple ID → iCloud → iCloud Drive, turned it off, restarted the phone, then turned it back on. After that, System Data dropped by a few more gigabytes, likely from clearing out duplicated or stuck local iCloud cache. Finally, I cleared Safari and app caches. In Settings → Safari, I cleared History and Website Data, then went to Advanced → Website Data and removed everything there. If you want to clean up even more, going through a few large apps and using their built-in cache cleaning options — or uninstalling apps you don’t really use — can help a lot. In my experience, WeChat is almost always the biggest space hog.(Tw93)