Dropbox corrupts Windows 10 Start Menu

I have the same issue as well, with the same behaviors.
Dropbox autoupdates; bug is back, uninstall dropbox, bug is gone, install dropbox all is fine, dropbox autoupdates, bug is back, uninstall dropbox, bug is gone, install dropbox all is fine, dropbox autoupdates, bug is back... etc ad nauseam

This has been happening to me too—not just for pinned folders on the start menu but for any folder I open from the start menu (even by manually typing it in) except for the main drive. It appears to be a Windows bug that's being exacerbated by an annoying feature in Dropbox that isn't configurable. I only thought to consider Dropbox the culprit because it didn't start until after I recently installed Dropbox on my new computer after having left it alone for a while.

Here's the discussion on Microsoft's answers forum (see WillCampbell7's response near the beginning of page 3, since Microsoft has no permalinks):

Microsoft discussion of start menu not closing 

The problem therefore appears to be the "Send a copy" shell extension that Dropbox adds, which is interacting with a known Windows bug.

This is a request another user made to remove the context menu items:

https://www.dropboxforum.com/t5/Apps-and-Installations/Can-I-delete-the-Dropbox-context-menu-items-that-appear-when-I/td-p/642181

There appear to be two solutions. One is for Dropbox to either make the context menu item removable like it should be. (I don't know why certain shell extensions have an issue and others don't. That's something Dropbox should investigate if possible.) The other is to block the shell extensions entirely, which I haven't tried yet but I intend to as it appears to be the only workaround for now. I can't keep having folders opening in the background.

Okay, update: I blocked the shell extension and restarted Explorer. Oddly, the context menu still appears, but the bug with the start menu has gone away (at least for now). Following instructions similar to those on the aforementioned Microsoft discussion:

1) Open the registry editor.

2) Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions\Blocked (create the Blocked key if necessary)

3) Create a new string value "{ECD97DE5-3C8F-4ACB-AEEE-CCAB78F7711C}", and give it a value of "DropboxExt".

4) Go to the Task Manager's details tab, right-click explorer.exe, end task.

5) Still in Task Manager, go to File | Run and type explorer.exe to restart the taskbar.

After I did this the start menu was behaving properly again. If it fails to keep doing so I'll follow up.

Unfortunately the problem has returned. I still think Dropbox is the primary reason for it, because it didn't start until I installed Dropbox. There are other shell extensions Dropbox adds that maybe need to be disabled, but unlike the context menu extension I don't know if it's as safe.

I am however still seeing "Send a Copy..." in my context menu, so it's also possible that the instructions I was given for disabling certain shell extensions are simply incomplete.

Sorry to hear that, JCplusULTRA.

Can you actually send us a screenshot, to show us how it appears for you?

A screenshot of the folder opening behind the start menu, for example, would have been helpful. 

Also, are the pinned folders, folders from your Dropbox? Or does this happen with any kind of folder you pin to your start menu?

I don't see how that would be helpful at all. I've uninstalled and reinstalled anyway, so we'll have to wait for it to rear its ugly head again.

Any and all folders, dropbox included, pinned to the start menu will not close the start menu until dropbox is uninstalled.

---

JCplusULTRA wrote:

I've uninstalled and reinstalled anyway, so we'll have to wait for it to rear its ugly head again.

---

Have you left it uninstalled for a few days, to make sure it doesn't happen when Dropbox isn't installed? If it's consistently failing after a days, leave it uninstalled for at least that long and see what happens.

OK, it's started again. I will leave Dropbox uninstalled for a week.