You data must be in text format....Try the below..

--Copy a blank cell
--Keeping the copy select the range of cells with numeric values
--Right clickPasteSpecial
--Select 'Add' and click OK.

--
Jacob


"raaaabert" wrote:

I get this alot, and Ive searched everywhere for the answer.

No macros or hidden sheets active.
Manual calculation is not on, it is set on Automatic.
I've tried F9 for posterity, with nothing happening.
I've tried CTRL-ALT-SHIFT-F9 also nothing.

The cells Im working on have been imported from an external source, ie they
are not hand entered but I dont think this is the issue.

They are custom format though, i.e. h:mm:ss.
Once I double-click on the cell and hit return the formula works but never
before.

PLEASE HELP!!!!