Great a little closer. I noticed weird things were happening with "myF" and "myfile".
So how do you say not this: ^medium$|^tiny$ <-- meaning if I do the following, it comes back as valid if I type in "medium" or "tiny", but I need it to come back invalid. So with the following if I type "sdkfldf" it shows as invalid as it doesn't match and if I type "tiny" is shows as valid as it matches.: <mx:RegExpValidator id="reservedNamesValidator" source="{nameOfFileInput}" property="text" expression="^medium$|^tiny$" flags="i" noMatchError="{nameOfFileInput.text + ' is a reseverd name'}" trigger="{saveButton}" triggerEvent="click" /> I want to say