Surface Pro 4 - External screen keeps turning on/off (black flickering)

OK so that would explain why you're not stable like we are. We have a higher version than you and it's only been on this version that my SP has ever been stable with a 4K display so until you get to that version I guess you'll have issues.

Either you're not on the latest version of windows or perhaps you're in a region that uses a different driver for some reason.

Can you check your windows version? I'm on the latest public released version (only came out about 2 weeks ago but I've had it for a month as I'm an windows insider) . If you go to settings, system, about you can find this information

Edition: Windows 10 Pro

Version: 1803

OS Build: 17134.48

James, thanks for the reply. I'm on v1803, latest stable, but I'm not an insider.

Do you think your graphics driver updated due to an insider update?

I've tried updating the graphic driver the last stable release (whatever was before v1803) and it wouldn't stick. I was having issues with Adobe Illustrator GPU performance, and a previous fix of downloading the latest driver from Intel and updating manually worked and solved the issue (2 versions ago), but I believe Microsoft removed the ability to manually update in the last stable release (the one before 1803). So not sure if we're able to manually update the graphics driver to a newer version in v1803.

Can anyone confirm if they've managed to manually update the driver to a newer version?

I'm not a Windows Insider and my update was fine. I found this page which will allow you to download just that driver

https://www.catalog.update.microsoft.com/Search.aspx?q=intel+corporation+driver+update+for+intel+hd+graphics+520 

It is the 6th one down on the page (22.20.16.1749). Interestingly there are newer versions, but this is the one that came with the 1803 update.

This is assuming that it was the graphics driver that fixed the issue vs something else. You may still want to figure out why your 1803 was not updated in the same way. Let us know how you get on. I feel a sense of responsibility and guilt knowing mine is working and yours should. ;-)

I have the same build (Windows 10 April 2018 update, version 1803 build 17134.48) and have been suffering through the external monitor on/off problem with Iris Graphics 540 driver 21.20.16.4627.

I think I "fixed" the problem by reverting to an older driver.  

In Device Manager under Intel Iris Graphics 540, under Driver, I selected "Update Driver" and "Browse my computer for driver software" and "Let me pick from a list of available drivers on my computer" and I still had a couple older drivers installed.  I selected driver version 20.19.15.4326 from 11/18/2015 and so far both my external and tablet display have been stable.  I am sure I am missing out on some performance or features in the newer driver, but I'd much rather have one that doesn't fritz out!

Maybe you could go forward to 22.20.16.4749. This is the version that works for me... It's not a new driver either (2017), but newer than yours.

I'm not a Windows Insider and my update was fine. I found this page which will allow you to download just that driver

https://www.catalog.update.microsoft.com/Search.aspx?q=intel+corporation+driver+update+for+intel+hd+graphics+520 

It is the 6th one down on the page (22.20.16.1749). Interestingly there are newer versions, but this is the one that came with the 1803 update.

This is assuming that it was the graphics driver that fixed the issue vs something else. You may still want to figure out why your 1803 was not updated in the same way. Let us know how you get on. I feel a sense of responsibility and guilt knowing mine is working and yours should. ;-)

I also have build 17134.48 so not sure why I dont have the same graphics driver.

also, just to clarify, you mean 22.20.16.4749 not 1749 (I think you had a typo in your last post)>

I'm downloading now and will try to update and see what happens. thanks!