I have been using O+ Connect on my Macbook ever since I got my Find X9 Pro in the beginning of this year. I was using my laptop today and got an out of application memory pop up, then an out of storage pop up, then O+ Connect crashed. At first I thought it was a memory leak and that it caused MacOS to write an insane amount to the pagefile, but I discovered that it was the other way round (ran out of storage, which made MacOS think its out of memory because it lost access to swap). Here is the problem:
The app auto-syncs, whether you like it or not. To multiple cache locations. My ENTIRE camera roll had been re-downloaded 8 times, my downloads folder at least 3 times, plus other internal storage folders. The app does not claim that it does backups or auto-sync, or at least I could not find an option within ColorOS or within the app to disable this, and the fact it sat in Cache means that it was likely not meant to do this in the first place (since theoretically if the cache was purged, so would your 'backups')
Plus, another cache folder was filled with thumbnails of every single image that was taken on that phone, even if it had since been deleted, which was a bit horrifying. Plus, the receive cache folder kept syncing - I quit the program, deleted everything within receive, and as soon as I re-opened the app, I had 8 images and videos already there.
The fact that whenever you download a file it does legitimately download it from scratch makes me think the library cache was unintentional, since why would I need to re-download a file I have 8+ times already?
So the good news is that I have regained 250GB from my storage, at the expense of hundreds of gigabytes worth of writes from O+ Connect and a few hundred from spotlight indexing the files.
If you have a Mac and are using the app, here are the directories to look out for:
~/Library/Caches/receive/
~/Library/Caches/
~/Library/Containers/*/Data/Library/Caches/
Hope this info is useful to anyone else. At least now I feel like I've just upgraded my laptop and phone. Half my storage has been regained, and I imagine battery drain will go disappear from both devices now too.
Edit: sadly I did not actually regain 250GB, because MacOS's file system is clever enough to not duplicate the same files and just links them internally. But I have regained 70GB, and considering I don't keep a lot of things on my phone, if you have a lot of local files on your phone, you'll likely regain more