Hi, I've been looking into MultiByteFileStream for adding tests in this area, and have come up against what appears to me to be an anomaly. I ran the following 4 tests: FileStream fileNamed: 'test.txt' do: [ :str | str nextPutAll: '123'; crlf ]. MultiByteFileStream fileNamed: 'test2.txt' do: [ :str | str nextPutAll: '123'; crlf ]. FileStream fileNamed: 'test3.txt' do: [ :str | str nextPutAll: 'élève en Français'; crlf ]. MultiByteFileStream fileNamed: 'test4.txt' do: [ :str | str nextPutAll: 'élève en Français'; crlf ]. The results are: Input string Result Unix File Class Class Type --------------------------------------------------------------- FileStream '123' MultiByte- ASCII text FileStream MultiByte- '123' MultiByte- ASCII text FileStream FileStream FileStream 'élève en MultiByte- UTF-8 Unicode Français' FileStream MultiByte- 'élève en MultiByte- UTF-8 Unicode FileStream Français' FileStream Do operations involving FileStream as input always return a MultiByteFileStream? Thanks, Sheridan