Hello KHearty and DianneMc
Welcome to the Community Forum.
Can you please let me know if you are changing any other fields on the client's card as the error is "One or more fields exceed the maximum character limit" it could be referring to another field.
MYOB Business currently only supports 250 characters in the notes field. The current workaround is to copy the employee notes onto a separate document, such as a Word document or Notepad file. This allows you to keep a record of these notes outside of the file.
Once copied, the notes can be removed or edited to be below 250 characters.
The error message should also direct you to which field is causing this error to pop up.