My Linux Cinnamon has just upgraded LO to 5.1.6.2
What has driven me crazy, in Writer (at least so far) the page colour on the screen for all my documents has changed from white to grey.
How can I get it back to white? Why did it change anyway? Have I screwed something up?
Tools > Options > LibreOffice > Application Colors :: General > Document Background
Why did it change anyway?.. My Linux Cinnamon has just upgraded LO to 5.1.6.2
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Probably the Office user profile folder has got some wrong information. If there is something weirder than before you should rename/erase it so that LO can generate a new one.
Have I screwed something up?
One never knows… 
Thanks for the straightforward answer.
The document colour already said white, but I changed it to another colour, then back to white again.
Now seems OK, thanks again.
So I did have to play around with some things, as I was having the same problems. What you have to do to fix this is to (as soon as you open the app, do not open a document) go to ‘tools’, ‘options’, ‘appearance’. There will be a dropdown menu under customizations called ‘items’. Make sure it has ‘document background’ selected and change the color to white instead of dark.
I am assuming the new update changed it so that the default color is ‘dark’ for some reason haha. I hope this helps anyone who is trying to fix this little bug!
You added this to a 7 years old thread concerning LO 6.2. Dark mode was introduced in 7.5 (in testing before), so this topic is now handled very much different… (Especially using system default to configure dark mode).