How do I validate and download a fixed file?

Open /fix, upload your .ics, review results, then use “Download fixed file” if it appears. Some issues cannot be auto-fixed.

Why won’t my calendar import?

Most import failures are due to missing or invalid required fields (e.g., DTSTART, VERSION, UID) or invalid time zones. Fix the first error shown or use the fixed download.

ICS Help & Guides

Practical guidance for fixing broken ICS files, resolving calendar import failures, preserving event behavior during migrations, and generating compatible iCalendar data.

Fix an .ics now ICS validator CorrectICS website support

Fix an ICS import problem

Start with the broad error router or match your current symptom

ICS file errors: choose your symptom Broad error and troubleshooting router

ICS file won’t import into Google Calendar or Outlook Fast troubleshooting guide

Fix “Invalid ICS File” errors Structural and field-level error reference

ICS validation failed or file is invalid Validation failure workflow

Import created duplicate events Post-import cleanup and prevention

Calendar apps

Route Google Calendar, Outlook, and Apple Calendar import behavior

Common ICS import errors by calendar app Google Calendar, Outlook, and Apple Calendar router

Outlook says VTIMEZONE is missing Outlook / Exchange compatibility

Time zones and recurring-event behavior

Fix wrong event times, invalid TZIDs, missing VTIMEZONE, and DST-related failures

Events appear at the wrong timePlain-language timezone and DST troubleshooting

Fix ICS timezone errors (TZID / VTIMEZONE)Timezone identifiers and embedded definitions

TZID=EST is invalid: use an IANA timezoneTimezone identifier reference

Calendar migrations

Preserve events, recurrence, and time zones when moving calendar history

Why calendar imports break after migrationMigration overview for duplicates, time zones, and recurrence

Google Workspace to FastmailMigration walkthrough and repair path

Google Workspace to Microsoft 365 / OutlookOutlook import checklist and repair path

Google Workspace to Proton MailPrivacy-focused migration troubleshooting

Google Workspace to Zoho CalendarZoho import and migration guidance

30-year Google Workspace to Fastmail case studyDetailed real-world repair workflow

Open and understand ICS files

File basics, calendar import steps, and validation workflows

Open an .ics file and add it to a calendarUser-facing how-to

What is an ICS file?iCal and iCalendar format overview

Validate an ICS file and fix import errorsCore validator workflow guide

iCal / iCalendar validator guideAlternative terminology and validation entry point

Developers and iCalendar format

Generate, debug, and validate ICS files in production workflows

Generate ICS files that import cleanlyAuthoring rules and templates

ICS import checklist for developersProduction export and debugging checklist

Validate ICS files in an app or workflowDeveloper automation and API path

Getting started

Tip For a quick fix, go straight to /fix and upload your file — no deep reading required.

The basics

What is an .ics? It’s a calendar file format that stores events. Most calendar apps (Google, Outlook, Apple) can import it.
Validate & fix a file: Go to /fix, upload your .ics, review the results, and click Download fixed file if offered.
Is it safe? Ordinary anonymous validation runs in memory. Saved repairs and large asynchronous jobs use temporary storage with limited retention. See Support for file-handling routes.

Popular how-tos

Export from Google: Calendar settings → your calendar → Export → download .ics.
Export from Outlook: File → Open & Export → Import/Export → Export to a file → choose iCalendar (.ics).
Export from Apple Calendar: Select calendar → File → Export → Export… → save .ics.
Merge multiple .ics: Zip them and use the Bulk tab on /fix, or open each file in a text editor and copy events together.
Inspect events: Open the file in a text editor; each BEGIN:VEVENT…END:VEVENT block is one event.

Troubleshooting

Common error types explained

DTSTART / DTEND issues

Events need valid start and end values. Missing, malformed, or inconsistent timestamps are one of the most common reasons an ICS file fails to import.

TZID problems

Time zones need valid identifiers like America/New_York. Aliases, abbreviations, or missing VTIMEZONE blocks often cause cross-calendar failures.

RRULE errors

Recurring events need valid recurrence rules such as FREQ=DAILY. Broken RRULE values may import partially, repeat incorrectly, or be rejected outright.

UID / PRODID missing

Missing IDs can make events hard to track or de-duplicate. CorrectICS can generate safe defaults when repair is possible.

CorrectICS website and account support

Account, billing, privacy, API access, status, and contact routing

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