What a really dumb title to write. But it is what happen in my SharePoint 2010 site.

I tried to create a calculated column in the Pages library of a publishing site. The idea was to allow filtering on the Modified Date. So my Calculated column held an easy formula.

=[Modified]

The problem was the Modified Column wasn’t showing up in the list of available columns to calculate with. Strange isn’t it!

And if I try to created it anyway, I’ve got this error:

FatalError: One or more column references are not allowed, because the columns are defined as a data type that is not supported in formulas.

After hours of research, countless backup / restore, iisreset and so on, I’ve managed to fix the problem in a simple dumbest way.

Go to the root site and change the URL after the DNS name for /_layouts/fldedit.aspx?field=Modified

Click OK and voilà.

By doing this action, SharePoint resets all the properties of the column in all subsites.