General Data Loss
- Dragging events that span more than one day will shorten the event duration (bug 323696). Workaround: change the time of an event that spans more than one day by double-clicking it and manually editing the start and end times in the dialog box.
- On Windows, events sometimes show up at the wrong times if you have "Automatically adjust clock for daylight saving changes" unchecked in the Timezone tab of the Date and Time control panel (bug 326868). Workaround: check the "Automatically adjust clock for daylight saving changes" box.
- Shutting down Thunderbird does not wait for pending calendar writes to complete, which could cause calendar corruption. Workaround: wait 5 seconds after the last calendar modification before exiting Thunderbird (bug 328810).
- Multiple users or computers editing the same calendar can collide and cause data loss (bug 329570).
- Alarms on recurring events often fail to fire, display, or be edited correctly; they should not be relied upon (bug 329985).
- Delete a local calendar. Create a new one. The old events show up in the new calendar (bug 296202). Workaround: create the new calendar before deleting the old one.
- Default timezone guessing is unreliable, especially in the southern hemisphere (bug 328996). Note that all events that you edit or create will end up in the default timezone. Workaround: manually set your timezone in the Lightning panel of the Options or Preferences dialog.
- Setting your timezone manually does not completely take effect until Thunderbird has been restarted (bug 329669).
- Outlook is unable to import some CSV-formatted calendar data exported from Lightning (bug 325484).
- If one moves an event after dismissing the alarm for it, the alarm may not re-fire before the event as expected (bug 326352).
- Lightning 0.1 will not work in the Japanese version of Windows 2000 if the date separator in Control Panel/Regional Options/Date is set to the slash character. Workaround: set the separator to the hyphen (minus) character. (bug 330121).
- On Windows 98, if your profile path contains non-ASCII characters, Lightning will not work (bug 329898). Workaround: create a profile in a directory that contains only ASCII characters.
- It is not possible to cancel the 'All Occurrences'/'This Occurrence' dialog. Pressing escape or clicking on the window close box acts as though 'This Occurrence' was selected (bug 329642).
- All-day events for yesterday are also displayed in the 'Today' section of the agenda tab (bug 330496).
Data Loss / Crashes Handling non-Lightning ICS Data
Lightning is not really ready to be used to modify ICS data that it did not itself generate. If you decide that you want to do this anyway, here are some things to be aware of:
- Editing floating or UTC events causes them to be moved to your default timezone (bug 304486).
- VALARM support is not yet complete (bug 308538). Importing or modifying calendars that contain VALARMs created by other programs will either fail or strip out any non-understood data.
- VTIMEZONE data produced by programs other than Lightning will be generally be read and understood, and should in theory be preserved, but this is not well tested (bug 314339).
- VEVENTs with a DURATION but no DTEND are converted to DTSTART+DTEND-style events upon importing or editing a calendar that contains them (bug 317786).
- Inline attachments and attachment parameters will either cause errors or be stripped out when importing or editing a calendar that contains them (bug 319909).
- X- components are stripped out when editing or importing a calendar that contains them (bug 322837).
- X- parameters are stripped out when editing or importing a calendar that contains them (bug 322831).
- X- properties and X- components can trigger crashes (bug 314334).
CalDAV has not been a focus for version 0.1; CalDAV support is currently very basic and has many issues. In addition to the various problems described in the non-Lightning ICS section above, other things to be aware of include:
- There is no UI to specify a username and password for a CalDAV account (bug 308567). Workaround: specify both the username and password in the calendar URI. Note that this workaround is a poor idea from a security standpoint. Be sure to URL-encode appropriate characters (e.g. the @ symbol).
- Editing recurring items may fail or lose data (bug 327990, bug 328576). No workaround known.
- Lightning may inadvertantly strip out server-side item changes that happen after a PUT.