hi Skjetve
your question
"How do you lock a cell, so the user can only write positive numbers in it?"
data validation do lock the cell while writing a negative number, what it
can not lock the cell for pasting a negative number
(pasting in excel is a short and productive way of writing data in one or
group of cells)
you can use conditional format for your visual check of mistakenly pasted
negative number.
Mr. Ken Wright do give a good advice.

Happy holidays.

"Ken Wright" wrote:

You've already been given the answer of DV, BUT, be aware that DV is easily
bypassed, and the user could simply copy a cell with a negative number and
paste it straight over that cell which will effectively remove the DV.

--
Regards
Ken....................... Microsoft MVP - Excel
Sys Spec - Win XP Pro / XL 97/00/02/03

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It's easier to beg forgiveness than ask permission :-)



"Skjetve" wrote:

How do you lock a cell, so the user can only write positive numbers in it?