High contrast/defender

I've just checked for you. No, in 16299.334 Defender still opens with a blank screen in High Contrast #1

Edwin said:

WD is not blank in High Contrast here...

What build do you have? Which High Contrast theme are you using, 'High Contrast #1' or 'High Contrast #2'? Only 'High Contrast Black' and 'High Contrast White' seem to work in 16299.334.

Edwin said:

Build 17639.1000
'Digital Art' High Contrast Theme

You are on an Insider skip ahead build (which will one day lead to version 1809) plus you are using a custom high contrast theme. Either or both of those facts would explain why it works for you.

This has been an ongoing problem for @dmesal since getting the Fall Creators Update last October, when I first investigated this for the OP.

The conclusion then was that, for the four standard high contrast themes built into the 1709 retail build either of the first two (High Contrast #1 and High Contrast #2) would case Defender to crash. Testing today with the latest 16299,334 build, Reliability History shows that it still does.

Description
Faulting Application Path: C:\Windows\SystemApps\Microsoft.Windows.SecHealthUI_cw5n1h2txyewy\SecHealthUI.exe
Problem signature
Problem Event Name: MoAppCrash
Package Full Name: Microsoft.Windows.SecHealthUI_10.0.16299.334_neutral__cw5n1h2txyewy
Application Name: praid:SecHealthUI
Application Version: 10.0.16299.334

The other two (HC Black & HC White) do work, but don't meet the OP's visual preferences. As before back in October...

...The bug only stops it opening. You only have to change to a different high contrast theme to start Defender Security Center, once it has started you can switch back to your preferred desktop and it will continue to work normally while it is open...

windows defender security center dosn't start correctly - Page 2 - Windows 10 Forums

The only change any cumulative update has made since October is that in HC#1 or HC#2 Defender doesn't crash immediately, but will now do so if you try to find any of its controls on the 'blank' window then click on them.

It would be interesting if any Insider with the release preview of 1803 could test to see if this has been fixed for the Spring Creators Update, due to be released this month. It won't help dmesal while still out at sea (I suspect data charges would be prohibitive) but it would be something to look forward to on return to dry land.

Good news, it works normally under 17133.1.

You should be able to upgrade by next week.

Edit: Upgrade (setup.exe) or clean install.