01
Validate the file
Upload, paste, or drop in an ICS or iCalendar file. Validation is free, so you can check it before deciding what to do next.
ICS, iCal & iCalendar validator
Validate your ICS file — and safely fix supported issues
Check or test an ICS, iCal, or iCalendar file and see exactly what is wrong with its formatting, time zones, recurrence, or import compatibility. When CorrectICS can safely repair the problem, it verifies the improved file before offering a download.
Free validation and clear diagnostics Anonymous validation runs in memory Verified repair available when supported
Start with the problem you see
CorrectICS can diagnose these common file and import symptoms. Some can be repaired safely; others require a manual publisher or platform change.
🟦 Google Calendar
ICS won't import into Google Calendar
File uploads but events do not appear, or Google rejects it with a vague error.
🟪 Outlook
Outlook ICS import fails or is incomplete
Only some events import, or Outlook throws an error on the file entirely.
🍎 Apple Calendar
Apple Calendar won't open the .ics file
macOS says the file is invalid, or it opens but nothing gets added to Calendar.
📅 Duplicates
Duplicate events after importing
Your calendar shows the same event multiple times after importing the ICS file.
🌐 Timezone
Events showing at the wrong time
All-day events or meetings appear at incorrect times due to timezone issues.
📂 General
The file won't open on any platform
Something structural is wrong with the file, such as missing headers, malformed events, or bad line endings.
How it works
02
See what is wrong
Review clear diagnostics for structure, required fields, time zones, recurrence, formatting, and common import problems.
03
Safely repair supported issues
When a safe automatic repair is available, CorrectICS can attempt it and verify whether the file actually improved.
04
Receive verified output
A repaired download is offered only when verification confirms a customer-deliverable result. Otherwise, you keep the honest diagnostics.
Problems we check and may safely repair
Repair depends on the exact file and is offered only when CorrectICS can verify an improved result.
- Invalid RRULE, DTSTART, and DTEND fields
- A common reason calendars silently reject an ICS or import only partial events.
- Timezone mismatches and TZID errors
- The hidden timezone problems that often break cross-platform calendar imports.
- Line folding and line ending errors
- Long lines and incorrect CRLF handling can break strict parsers.
- Event property normalization
- Event fields are brought into cleaner, more standards-friendly shapes where safe.
- Multi-event structure problems
- Malformed BEGIN:VEVENT / END:VEVENT blocks can cause only one event to import.
Privacy
Processed in memory
Ordinary anonymous validation runs in memory. Saved repairs and large asynchronous jobs use temporary object storage for 24 hours on Guest/Free or 30 days on paid plans.
Minimal logging
Logs contain request IDs and operational status only, not calendar payloads.
Encrypted in transit
All uploads and downloads happen over HTTPS.
Building something with calendars?
CorrectICS also has an API for developers who need validation and supported autofix in production workflows.
Simple REST API
POST a raw .ics to receive machine-readable validation results and verified repaired output when supported.
curl -X POST "https://api.correctics.com/api/validate-ics?autofix=1" \
-H "Authorization: Bearer $CORRECTICS_KEY" \
-H "Content-Type: text/calendar" \
--data-binary @meeting.ics