The uninstall captcha is just displaying a black window

The reason the captcha shows a black window is to protect NeuShield from remote removal.  We block the captcha from showing through any remote desktop or screen imaging tool to prevent an attacker from remotely accessing the system, uninstalling NeuShield and then installing ransomware.

To see the captcha you need to be physically at the system looking at the monitor.  Alternatively, if you are using the Home or Business edition you can enable the password uninstall and then remotely uninstall using a password, rather than the captcha.

Here are the steps to enable the uninstall password:

1. Logon to your account on the NeuShield portal.
2. Go to the "Data Sentinel Settings" tab.
3. Click the "Configure" button under the Uninstall Control section.
4. Select "Uninstall password" and type in a password.
5. Click "OK" and then "Save".

For scripted uninstalls check out this article:  How to uninstall NeuShield from a command line (CLI)

Also see:  How can I uninstall NeuShield from Remote Desktop?