I am using Excel 365 on windows 10 and when I open the spreadsheet the colours chosen by my use of Conditional Formatting are present, but after some movement from cell to cell the colours in the Conditional Formatted cells revert to white. Unusually if I then go to preview a Fill colour they all reappear but only whilst the cursor is on one of the preview Cell Fill colours , but when moving off these the colours disappear again and only reappear when the sheet is closed and re-opened again. They do not remain for long when you move around the cells!?? Any help would be great.