Cells linked between sheets -- virus or feature?

I have cells in a workbook that seem to be unintentionally linked between worksheets. It seems like a virus but maybe it's a feature.

The workbook has one sheet per month. I have maintained this workbook for the past year. To make the sheet for next month I use the format,copy command and then modify the entries for the new month as necessary. I have never linked the cells between the sheets for different months.

Today I noticed that when I change a cell on the "April 2012" sheet, the same data is entered in the same cells on all the sheets going back to "December 2011" (but not for other 2011 sheets). For instance, if I enter "99" into cell C89 of April 2012, then cell C89 of the sheets for the preceding several months will also contain "99." There is no indication within the cells that the cells should be linked.

I keep a back-up copy of each months workbook. I do not see this behavior in the workbook whose last worksheet is March 2012.

Any idea what might cause this??

Thanks,

Jim

Good afternoon jimpgh

...and welcome to the forum!!

Have you entered this in "Group mode" ie, when you hold down Ctrl and select several sheets, when you change a cell, this changes the relevant cells in each sheet.
If so, it's a feature, but one that does catch people out.

HTH

DominicB

Solved -- I had grouped all the worksheets together and needed to "ungroup" to stop the simultaneous updates.
Thanks!