This sounds exactly like my issue. Things are slow because Dropbox is totally thrashing the registry. Right-clicking on the desktop (or opening the Start Menu) requires checking a few dozen registry entries, but Dropbox's indexing causes a kind of denial-of-service attack on the Windows registry. Dropbox support was pretty cool when we started talking offline and we were able to track it down to Windows being the real troublemaker. When Dropbox checks a file during re-sync, it sends out a request to Windows to update the little icon in the corner (green checkmark, etc.). Historically, this was fine. Maybe(?) after the latest Windows 10 update (that's my guess; the Dropbox team reported they haven't been able to reproduce the behavior), that exact same "hey, Windows, update that file's icon" request now involves checking the registry for four values, which ends up closer to thirty actual registry operations. Who knows why. Windows doesn't seem to cache the values, so it repeats the check for every file. And Dropbox seems to update the whole folder hierarchy's icons each time (despite alleged "deduplicating logic"), so you end up with something close to 150 registry calls per file in your Dropbox! No known workaround. All we'd need is an "I don't want icon overlays" option in Dropbox and this problem would disappear. Alternatively: Windows could fix its broken code.
... View more
I found most of the advice (including the permissions reset under #3), on this page. The copy was done using xcopy (specifically, from the new computer, over a network share "xcopy /b /c /e /h /i /k /s /x /y /z Dropbox D:\Dropbox") and again for the AppData\Local\Dropbox folder. I was hoping everything would just carry over automatically. At first, it appeared to work just fine. During the first launch wizard, it even had my selective sync folders correct already. I believe my "installation" method is unrelated, but I do see your point that there are a lot of non-standard moving parts in my problem description. So, over the weekend, I tried to simplify my case to rule as much out as possible: I uninstalled Dropbox on the new machine, made sure the D:\Dropbox folder and the AppData\Local\Dropbox folder were completely deleted, and wiped out any lingering mentions of Dropbox I could find in the registry. On the old computer, I spent a few hours trimming the number of files down considerably. (There were several groups of a few (or ten!) thousand small files I wasn't actively working with that made sense to zip into a single file instead.) I let those changes (bringing my Dropbox file count down from 330k to 140k) completely finish syncing overnight. I performed a clean install of Dropbox on the new machine, pointed it at D:\Dropbox and let it do everything itself (using LAN sync). I'm still a few hours out from that initial sync completing, but the registry craziness started again almost as soon as the app was launched. Looking more closely, (now that the sync is down to just the bigger files and things are moving a little more slowly), that pattern of four registry checks seems to be happening four to six times per synced file. If you include the surrounding hkey open/close calls, that means Dropbox is making 144 registry calls to the Windows kernel per synched file, which seems a little... abusive. Filtering out all but one of the calls, you can see each block of events grouped by timestamp: With the Dropbox popup open at the same time, you can see the burst of activity happen at the same time the "Syncing X files" counter changes. I might suggest you cache those four values instead of attacking the computer. We'll see after the sync is complete whether it continues. With about 1,600 (of the largest) files to go out of 140k, the Dropbox process is sitting at "only" 1.8GB of RAM, so we may be able to chalk the crashing up to the large file count. That simplifies the story even more.
... View more
I've been having the popular "constant high CPU usage, even when finished syncing" on Windows 10. I checked the list of seven possible causes and none of them apply (except maybe "lots of files" with around 300k files). There aren't any symlinks.
To see what Dropbox might have been up to, I ran Microsoft's "Process Monitor" utility. It appears the process is checking the same four registry entries in a loop, hundreds of times a second. (This admittedly makes many normal operations take much longer--like right-clicking the desktop and waiting 5+ seconds for the context menu--because Dropbox is essentially performing a denial of service attack on the kernel by flooding it with Win32 registry calls.)
The registry values are:
I couldn't find any documentation on what those registry entries are, should have for values, or anything else about them anywhere on the Internet.
The Dropbox process' memory usage also appears to slowly grow without bound until after ~40 minutes, it crashes once it hits 4GB or so.
This is a new install on a new machine. I copied my old Dropbox folder from the previous computer (over the network, manually) then installed the Dropbox client and pointed it at the copied folder. It was working fine until after the first reboot. I eventually found the community post about resetting permissions. That didn't change any behavior. From very nearly after the app is started right up until it crashes, those four registry entries are constantly assaulted.
If anyone has any suggestions, I'd love to hear them!
Dropbox v86.4.146 / Windows 10 Pro
... View more