How do I change the Windows 8.1 background color?

When I lock my computer and I go to the login screen there is a purple colored background. How do I change this?

I set this when Windows 8.1 was first installed.

3 Answers

Press Win+W and type accent in the Search box on the right, and select Change the Background and colors on Start. Click on it and change the color.

Alternative method:

Press Win while viewing the Desktop and you will be taken to the Metro Menu. Press Win+C → Settings → Personalize → Choose your color.

This is a variation of the method posted by Devid. On my Windows 8.1 Pro computer I was unable to click on the "Change the background and colors on Start" link, as noted. This is high likely a bug. So I will show a slightly different way to access this setting, and also post some nice screenshot.

1. While viewing the Desktop, press the Windows key to show the Start screen.
2. Move your mouse pointer to the upper right corner of the screen and move it down.
3. Click on "Settings", and then "Personalize" at the top.
4. Pick a "background color".

Take your mouse p[ointer to the extreme right. Click Settings. Click Change PC Settings. Click PC and Devices on the PC Settings app. Choose the image you like, and exit. If you want to use your image to set as lock screen background, hit Browse button below lock screen images.