For branding reasons all documents in my company have a specific color pallet, when you open those documents in CALC, some cells change color
We are using Libreoffice 4.4 on 25 machines.
Do you know the RGB values of the changed colors?. Please try adding it to the palette in Menu/Tools/LibreOffice/Colors.
MS EXCELL does not support ODF fully.
A possible workaround could be to write a macro which changes the background to company color and is exevuted by clicking an icon.