Thanks ArchAngel for your suggestion.
I have done that, which certainly corrects the past two days' data. However, today the same thing happened and the charts stopped at 16:00 although the Time & Sales continues until 16:15, so deleting the file corrects past data but is not an on-going solution.
I also do not have any data for the overnight sessions, which is particularly frustrating as well.
Has anyone else had this problem?