What does have multiple selections on mean?
If you're trying to show a field if it's False, then you might want to also include null checking, as False and null are different things.
Try:
If {table.field} <> True then
{table.field}
else If {table.field} = True then
true
If you're trying to limit the rows returned from the database, use Report->Edit Selection Formula->Record:
(
{table.field} <> True
)
As LB points out, your post is very vague, for the best results here, try posting Crystal Version, Database type and version, example data and expected output. And if you've tried a formula, state where and show what you tried.
-k