The Yes/No type field is a boolean type. And the True value of booleans in Access is "-1", not "1" as in many other languages.
Need something like:
If StillActive=-1 then append to table1
If StillActive=0 then append to table2
Do Nothing, must be a null value.
Could do 2 separate MakeTable queries:
1. Select all where StillActive = -1
2. Select all where StillActive = 0
Sanity Check: Total Records in Table1 and Table2 = Total Rercords in original table. Any difference in count = Null values in StillActive.