Leaving the find field empty disables "replace" to be able to add text to all empty fields. A use case would be to replace emptiness with the word "none".
I found this 2010 era workaround, but the instructions about where to put the script leads to dead ends, so I assume things in the MacOS have changed 13 years later.
find and replace on empty cells - Apple Community
What is the best way to do this in Sonoma?
MacBook Pro (2017 – 2020)
Follow these instructions for installing the script.
This is very basic, it will only fill the selected cells (a whole table if you want).
set temp to display dialog "Replacement value" default answer ""
if button returned of temp is "OK" then
set replacementText to text returned of temp
tell application "Numbers"
tell every table of active sheet of front document
tell selection range
set (value of cells whose value is missing value) to replacementText
end tell
end tell
end tell
end if
Follow these instructions for installing the script.
This is very basic, it will only fill the selected cells (a whole table if you want).
set temp to display dialog "Replacement value" default answer ""
if button returned of temp is "OK" then
set replacementText to text returned of temp
tell application "Numbers"
tell every table of active sheet of front document
tell selection range
set (value of cells whose value is missing value) to replacementText
end tell
end tell
end tell
end if
Many thanks. Took a while to figure out, as I am unfamiliar with using Scripts. Works like a charm.
In Numbers, how to target empty cells and replace with text