Windows Dropbox installer won't start on Windows 10

[Roger B.30]

I run Windows 10 on a Dell Inspiron 3505 laptop. Somehow, Dropbox was not starting at startup. The simplest answer (to me, anyway) was to uninstall Dropbox and reinstall it. I uninstalled DB and downloaded the installer (which has always worked for me before) from the website (as  I always have) .and ran it; I got a message that the installer did not start. I've tried several times but always got the error message. In the past, Microsoft Defender has given me no resistance to installing DB. What's wrong--is it me, the installer, or something else?

[Walter]

Hey @Roger B.30, sorry to hear about this.

Could you please try reinstalling the desktop app, using the offline installer from this page and let us know how it goes?

If you're on the Basic plan, make sure to have no more than 3 devices connected to your account, as there's a device limit. 

You can also temporarily disable any antivirus or firewall you might have running on your computer during this process.

Let us know how it goes.

[Roger B.30]

Walter, I tried the offline download with Microsoft Defender turned off. I only have 2devices attached to my account. The offline installer also failed to start. What do I do now?

[Jay]

Hi @Roger B.30, could you try downloading the Dropbox desktop application from another browser entirely, while all antivirus software is disabled, and then try running it?

[Roger B.30]

I normally use Firefox; this time, I used Chrome (Microsoft Defender disabled). I got the same result--the installer didn't start. What now?

[Jay]

If you check the Task Monitor, does the process close immediately?

Have you tried rebooting the machine to see if this helps?

[Roger B.30]

Unfortunately, rebooting doesn't help; neither does System Restore.

[Walter · Accepted solution]

In that case, the next step would be an advanced reinstall at this point @Roger B.30

Could you give it a go and let us know how it goes?

[Roger B.30]

I did an advanced install, and it seemed to work. The system is uploading files right now, but it looks like quite a bit of my stuff may have disappeared.

[Walter]

Is the app 'up to date' or still syncing, Roger?

Do you see the missing files in your account on the website, be it in your homepage or the events page?