Solution

While everything is white on the taskbar, the clock turned black and so became almost invisible after the last automatic update (today, sept 26, 2016).
Very annoying. Please help.

Are you using a theme ? Best to post a screenshot I think

Screenshot - Take in Windows 10 - Windows 10 blog

Did you try rolling back to a System Restore point before the update was applied. That taskbar area is coded in to not change, unless you use some kind of theme. Even then Microsoft keeps making it harder for people to tweak the GUI to their taste, by using the updates to change it back to how they want it to be.

Here is how it looks like. PLease note that my monitor screen is set to "dark", and in this mode the clock is all but invisible. It's barely visible when I reset my screen brightness to "default" but I don't want to do that.

I remember that I used a patch (a registry hack) to get borders to windows, but it was not affecting the taskbar.

Before the last update, the clock was white. yet I'm not going to roll back an update for that. There must be a solution.

Thanks for your help.

I found something: In the "Taskbar and Navigation" dialog, when selecting "Taskbar" there is an option to "use small taskbar buttons". If I disable this the clock become white as well as windows captions. I had the problem of having windows caption too dark a long time ago but I grew adapted as nobody had an answer for this.
The problem is that disabling making button smaller makes them bigger and I lose too much space on my taskbar. I realy don't want button larger.

Ok, I see.
My visual problem was a bit different to you, I was having problems with the clock/calendar popup.
Still, I will tell you what I did and you can give it a try, might help.
• Go to Settings > Personalization > Colors
• Turn Off Show color on Start, taskbar and action centerIf it's already off try turning on.
• Your accent color looks the same as mine (light blue) but if necessary choose a new Accent colora light one would probably be best but not Automatic.

Good luck

Thanks for your suggestion. Unfortunately, in my case the taskbar remains dark no matter what option I choose.

Clock turned dark, invisible after update... Please help.

I "use small icons on taskbar" ... disable ... I lose too much space on my taskbar. I really don't want button larger.

You can try this circumvention:

Thanks, I'll try it!For the moment I use the large taskbar buttons and got used to it.

MS solution >