Yes, ICS files from different calendar applications can usually be merged into a single file because the ICS/iCalendar format is supported by platforms like Microsoft Outlook, Google Calendar, Apple Calendar, and other scheduling tools. However, when combining multiple files manually, users may encounter issues such as duplicate events, broken recurring meetings, missing reminders, or formatting inconsistencies between calendar platforms.
A practical approach is to use a dedicated SysTools ICS Merger that helps to consolidate multiple calendar files while preserving event metadata, time zones, recurring entries, and attachments. This solution often considered for this type of task because they simplify the process of combining bulk ICS files into a single organized calendar without requiring extensive manual editing. This can be especially useful when migrating calendars, creating backups, or managing events from multiple sources in one place.