Why do the colors suddenly change in Microsoft Excel?

[dc4life78]

I have been dealing with an annoying problem with Microsoft Excel where, out
of the blue, the palette colors will change to different colors. I use
worksheets with a lot of highlighting, and often times the new colors will be
so dark that I cannot see the text. The only remedy is to change the colors
to something else or (what I usually do) close Excel completely and restart
the program. Does anyone know of a way to stop this, or at least an
explanation for why this even happens in the first place?

Thank you!

 

[ufo_pilot]

You may try TOOLS>OPTIONS>COLORS
There you have some options.
You can import another (opened) workbooks color pallete

 

[dc4life78]

I have already tried modifying the colors, resetting to default, importing
from other workbooks; nothing works. The color schemes simply change without
warning; for example, forest green turns into dark green (basically black)
and light orange becomes light grey.