The main killer of course being that they dropped support for exFAT, so there's zero way to use Dropbox on a drive shared between OS. That sounds a bit niche, but it basically means Dropbox can't be used on external storage.
Don't get me wrong, exFAT is dated. However, the supported file systems vary between OS, so you can't even use Tuxera (or FUSE) NTFS on Mac.
There's a lot of complaints about this on the Dropbox forums; so they know, they just don't care. So that's a black mark both technically and for customer support.
It seems like a situation where 95% of your users are covered by supporting a few partition types and a significant amount of time would be spent trying to do anythings more.
It is unfortunate they dropped exFAT support.
This actually doesn't make much sense as logically they ought to be depending on an abstract interface to the filesystem not a particular filesystem unless the filesystem in question actually lacks features required to make the software work.
This is actually so because it actually did work for years across a wide variety of filesystems. I was syncing files between one machine with ext4, one with zfs, and my android device without difficulty.
This is perceptibly to the user like websites that used to check to see if you were running internet explorer and auto fail if you were running firefox. It actually works if you fake the user agent.
Humorously you actually can work around the problem in the same fashion.
https://www.linuxuprising.com/2018/11/how-to-use-dropbox-on-...
However its easier and safer just to drop dropbox.
It’s no longer the universal solution it used to be. That was it’s one selling point its competitors didn’t have. Good job ruining it!
If my next phone is an Android, I’ll probably move everything to syncthing and call it a day.
I can't speak to Dropbox since I don't use it for much, but even if a filesystem has those features it's not always a good idea because of a support, q/a, performance reasons, or future features. I was just trying to give my own abridged version of "mistakes programmers make about X"
I know there are hacks to make it work with other FS but I can't trust hacks with my data.
I think I first heard of them with casync. The gist of it is that you hash file contents in a sliding window, and use a condition on the resulting hash to chunck your file. That way, blocks are determined by the file content, not an arbitrary offset, and this allows to propagate deltas even with insertions or removals.