I know it's careless but a friend has managed to do just that! We have checked the Options and the check box is ticked, we have checked to see if some nice person hs added a macro - nothing, we have opened a new workbook and the tabs are there, same for other existing workbooks.
Anyone any bright ideas? It's Excel XP and I suspect it's just had a moment and will need to re-create the workbook.
I had a similar problem with a report i inherited last year. It turned out that someone had used a 'veryhidden' function as an upon open function. Took ages to find out what it was. Have a look in the VBA window and see if that is the case (unless the last answer solved the problem). Unfortunately i cant remember how i fixed it probably something simple like removing the code but should be fairly easy to find the answer on the web.