Fix ICS time zone errors
If events import at the wrong time, shift by one hour, or fail in Outlook after working elsewhere, the .ics file probably has a time zone problem.
Common causes include ambiguous time zone labels, missing time zone context, daylight-saving transitions, and calendar clients that interpret the same file differently.
For a quick repair path:
What to look for
Time zone problems usually show up as:
- events shifted by one or more hours
- recurring events drifting during daylight saving time
- Outlook or Exchange rejecting a file that Google Calendar accepts
- imports that work on one device but not another
- local event times that lose their intended location context
Why this is hard to fix by hand
Calendar clients do not all apply the same rules. A file can pass a loose parser and still fail when imported into a stricter app. Time zone behavior also depends on recurrence, daylight-saving transitions, and the destination calendar’s own interpretation.
Hand-editing a single visible time zone label may not be enough. The file can also need matching time zone context and revalidation after repair.
Safe repair path
- Validate the
.icsfile. - Identify whether the issue is a time zone label, missing time zone context, recurrence drift, or a broader formatting problem.
- Generate a repaired file instead of repeatedly importing the broken one.
- Test the repaired file in the calendar app that originally failed.
CorrectICS can identify these blockers and generate an import-ready file when safe fixes are available.
Developer docs
Detailed time zone generation notes, examples, and API validation guidance are kept in authenticated Developer documentation:
Fix your .ics file in seconds
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