Recurring events wrong or rejected in a calendar import (RRULE errors)
Last reviewed 2026-09-19
Recurring events are described by an RRULE line with strict syntax. Calendars ignore or reject a rule that uses lower-case keys, full day names like Monday, an UNTIL in the wrong format, both COUNT and UNTIL, or out-of-range values, so an event that should repeat weekly shows up once, or not at all.
Messages you might see
- “Recurring events missing or repeating wrongly after import”
- “Invalid recurrence rule”
- “Calendar shows the event only once”
Why it happens
- Hand-written or script-generated rules with the wrong syntax.
- UNTIL given in a different time format from the event's start.
- COUNT and UNTIL used together, which is not allowed.
- Time-zone mismatches between the rule and the event.
Try this first (free, no tool needed)
- Compare with a recurring event exported by your calendar app and copy its syntax.
- Check that UNTIL matches the start's format (date versus date-time, and UTC).
- Import into a different calendar app to see whether the file or the app is at fault.
If that didn't work
These tools run in your browser. Your file is read and repaired on your own device and is never uploaded.
iCal Recurring Event Fixer
Repairs lower-case keys, day names like Monday, bad separators, UNTIL in the wrong format for the event's start, COUNT together with UNTIL, invalid INTERVAL and out-of-range BYMONTH or BYMONTHDAY values, and reports time-zone mismatches. It does not decide what schedule you meant when a rule is ambiguous.
Open iCal Recurring Event FixerCommon questions
Does it fix other calendar problems too?
For broken calendar structure (unbalanced blocks, missing wrapper, sloppy dates) see the calendar import guide and its repair tool.
Is my file uploaded anywhere?
No. The tool runs as a program inside your own browser, so the file is read and repaired on your device and never sent to a server.