Do you have a source for claim #2? Please share
Then page 3 has the following user report:
> I'm running Windows 10 and my Dropbox is located on my E drive (E:\Dropbox). I also notice high disk activity. However when I look in Resource Monitor I noticed that the high activity generated by Dropbox.exe is on the C drive (not E).
To which an employee says the reason is that dropbox is installed on C:.
> Although you have your Dropbox folder on your E: drive, the application is still installed on your C: drive, so that’s why you’re seeing the activity there.
Here is link showing more people reporting the same problem. Files being copied from one part of the file system to another and the Dropbox client consumes 60%-100% CPU. I cant even comprehend how that is possible.
I did not debug this or look at anything, so I can't tell you.
One plausible explanation is they are effectively polling Dropbox folder instead of blocking until actual changes occurr. So maybe that hogs CPU scanning the Dropbox folder at inappropriate times, meaning that other activity on the machine has to compete for CPU time and lock acquisitions with unrelated but very noisy requests from the Dropbox client.
The fact that some users say that adjusting ACLs might get their client "unstuck" would fit this theory. Maybe they had a bug that generates noisy scans on the disk when they get "access denied" in an unexpected place.
But really I have no idea.