I was looking for a reliable ICS splitter for a large calendar file, and I ended up trying SysTools ICS Splitter Tool. It worked well for me because I could divide the large ICS file based on event count, file size, date range, subject, organizer, or category. The process was straightforward, and the resulting files retained the calendar data. If you’re dealing with a large ICS file that is difficult to handle or share, this is one option worth considering.