1)I didn't remove KB4515384, it never installed on my system. Got error 0x80073701 at first place then after 15 times of failed update it stop appear when I press "check update"
2)Yes, I also tried clean the update temp folder, turn off auto update service-reboot-restart service, download the update package and install by myself - all didn't work.
3)I always let the system auto update, never turn it off.
My only hope is that 1911 can be force to update by windows 10 update assistant and Get everything patched. I can't trust the lousy windows update now....
1) I see, well that sucks.
2) Hmm, you can try ccleaner (you can download an old version off filehippo.com) I wouldn't recommend using it's built-in registry cleaner as these do more damage than good.
3) If you have 10 pro, I'd recommend using group policy to stop Windows Update auto updating as it's completely borked. As this way you can use the Microsoft's asinine troubleshooting tool, to hide troublesome updates temporarily which you can get here:
Support.microsoft.com/en-us/help/4027322/windows-update-troubleshooter
I presume moving stuff off dropbox and reuploading is not an option?
Lastly, is it possible for you to move the synced folders for Dropbox to another drive or partition?
You can find steps to move the drop box folder here:
help.dropbox.com/installs-integrations/desktop/move-dropbox-folder
Also can you access that location via other devices?
If not presuming you are using dropbox basic - which now has a three device limit, you may have to remove a device and add another PC as it looks like you can't move the sync folder to a removable drive.
help.dropbox.com/accounts-billing/settings-sign-in/computer-limit
help.dropbox.com/accounts-billing/settings-sign-in/unlink-relink-computer-mobile
However, I'm guessing you have multiple devices linked prior to the three device limit in that case you would have to either become a paid member or wait for next update to see if that fixes the issue.