Why I don't see default cell grid or borders
I opened an Excel file. A sheet that I am viewing has some cells with borders and some completely without them - white fields. After I added another sheet to this file that sheet appears as completely white. How do I introduce there default (grey color) borders, i.e., grids? Why I can't see them in this file vs. in a new file that I would open in LibreOffice? C:\fakepath\Excel Libre Transfer File Sample.ods
Default and other formatting is sometimes lost or changed when data is imported from a different program. Have you tried to highlight the cells in question, then choose menu Format -> Cells -> Borders? Choose an appropriate border arrangement and border characteristics, then click OK. Although I have not used it often, it has always worked for me (so far).
Your suggested action doesn't show default (grey borders) but only user defined borders.
Thank you.