mozman_1970

Thanks for the suggestion. I had already looked at this option and it is checked. I even tried unchecking and then checking it again. The strange thing is that it only affects all existing worksheets but not any new blank ones. I even tried uninstalling excel and re-installing it, with no change in the behaviour. Yet all the time I can see the tabs in other version of windows using the identical file.

mozman

Update: I solved the problem through trial and error. I was able to see the tabs again when I used the "full screen" option in the "view" menu, but of course the menu bar and ribbon disappear when you use this option. Using the short-cut ctrl+F1, I restored the ribbon and the tabs stayed. I still have no idea what caused the problem in the first place. Oh well ....