Conditional Formatting on Cells with data validation

Care to tell us what constitutes an error?
More likely than not, a CF formula can be developed, but we need to know more about what is an "error" in your worksheet.

Thankyou for your response,
The error display in the cell is text that i have specifed "Please choose a valid date", the colums prior are drop downs for month and date, based on the error, i would like those cells to turn red with white writing, if there is no error, the cells to turn green with black wrigting. I am unsure if it is possible with cells that have list values.

Any formula used in Conditional Formatting must evaluation to either TRUE or FALSE.
Simple example:
Invalid formula =A1+B1
Valid formula: =(A1+B1)>1

Unless your error cells are numeric, then you would need to use the Formula is option for CF.

Not knowing your cell references here is the idea:

CF Formula 1: =A1="Please choose a valid date"
Cf Formula 2: =and(not(isblank(A1)),A1<>"Please choose a valid date")

The second formula uses the AND function to test two conditions, both which must resolve to TRUE for the conditional format apply.
1 - A1 is not blank ( a selection was made)
2 - The selection is not the error

HTH,

Palmetto

That worked, thankyou Is there a way to have that same set of condition formatting to apply to multiple rows or would it have to be done individually?

To apply the CF to other rows in the same column make the "CF" cell the active cell then fill down as needed.

Thankyou again for your response,
It did not work for the fill option, it kept referencing the original "A1" cell. I can do it individually tho. Thankyou again for your assistance.

There should be no problem with filling down as the formula use relative (A1) cell references. Did you change them to absolute ($A$1).

Solved it, had to apply conditional formatting to each row, as it would not copy down based on cell values.