A Google Calendar import error does not always mean no events were added. Diagnose the reported result and destination before importing the whole file again. Repeated imports can complicate a migration when some records are already present and others need a targeted correction.
Record the actual result
Use a computer and note the message, source filename, destination calendar, and representative missing dates. Google’s troubleshooting guidance says Processed zero events can appear after a successful first import when Import was clicked again. Check the calendar before treating that message as total failure.
Inspect file structure and limits
For a ZIP export, extract the individual ICS files and import them separately. For CSV, check comma separators and the required English headers. The troubleshooting help documents a one-megabyte file-size limit; a smaller source date range can be preferable to casually editing a complex calendar file by hand.
A partially processed count can indicate unreadable records. Keep an unchanged source copy and compare specific entries rather than deleting the entire destination immediately.
Verify the corrected subset
Check dates, time zones, all-day spans, and recurrence against the source. Use the current Import and export interface from Google’s import guide rather than relying on older menu labels still present in some troubleshooting examples. Plan any reimport with awareness of records already added. Guest and conference information is not imported, and recurring records exported as one-time events remain one-time copies. The completed diagnosis should identify what succeeded, what failed, and the narrow correction needed, without declaring the whole migration complete from an HTTP response or repeating every source file indiscriminately.
References
Reviewed against the linked official product guidance on November 4, 2026. Features, limits, screen labels, and access can vary by account, platform, region, and organization policy.