If you set a field to Not modifiable, you can not change the field.
What is the purpose for you choosing that and what are you trying to accomplish?
Johan, thank you for your answer. I messed up. FileMaker won't let me modify the field. If I click on 'Field' 'Manage' 'Database' the field pops up: You must enter a value. How do I overwrite this? How do I redefine this field?
I just wanted a field that automatically enters serial numbers and I defined this filed wrong, but now FileMaker won't let me change it. Just the boxes pop up over and over and it won't let me access the menu where I can change the definition of the field
Ctrl-Alt-Delete then close FileMaker Pro
Oh. I think that might have worked. I deleted one record and that took care of to also. Because then nothing was selected and I was able to go back into 'Field' 'Manage' 'Database' and delete my field. Whew. Glad I got out of that one. Thank you very much for taking the time to answer me, Johan. Have a nice day.