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Can I restore a deleted lightning calendar?

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  • Last reply by GaryMfield

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I am running Thunderbird 52.7.0 and Lightning 5.4.7. I had a problem where duplicate "Home" calendars got created with one showing temporarily unavailable (yellow triangle). I deleted the wrong copy and now my calendar and tasks are empty. Is there any way to retrieve that information without going to last night's backup? And exactly where is the calendar and task data located? Thank you.

I am running Thunderbird 52.7.0 and Lightning 5.4.7. I had a problem where duplicate "Home" calendars got created with one showing temporarily unavailable (yellow triangle). I deleted the wrong copy and now my calendar and tasks are empty. Is there any way to retrieve that information without going to last night's backup? And exactly where is the calendar and task data located? Thank you.

Chosen solution

are there other files involved?

There are. The files above are just the calendar data. But you'd need to have the correct calendar definitions as well. This is part of prefs.js in your profile folder. I strongly advice not to mess with prefs.js manually, unless you know exactly what you're doing. So your best bet is to re-create the calendar exactly the way it was before the incident, even if it's empty at that point.

In the calendar-data folder I see two files. deleted.sqlite which is from the day before the calendar was deleted and local.sqlite which is quite a bit larger. Could that file simply be replaced from the prior nights backup

Once you have the calendar definition right, you can try to replace the files from the backup. I'd probably replace both files from the backup. Whether this works, I don't know. You'll have to give it a try. Make sure Thunderbird is closed when doing this.

Also create a full backup of your Thunderbird profile before you start messing with it. https://support.mozilla.org/kb/profiles-where-thunderbird-stores-user-data#w_backing-up-a-profile

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The easiest would be to restore a backup of the individual calendar. That would have to be created before the incident by exporting the calendar and save it in .ics format.

Beyond that, you can restore the backup of the entire profile.

The calendar data itself is in the profile underneath 'calendar-data'.

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Thank you for the response. I don't have a .ics backup of the calendar. In my case, this was a single calendar so no chance of messing up any other calendar. I do have a backup of the network drive that contains the calendar data. Can I simply restore the calendar from that backup? In the calendar-data folder I see two files. deleted.sqlite which is from the day before the calendar was deleted and local.sqlite which is quite a bit larger. Could that file simply be replaced from the prior nights backup or are there other files involved?

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Chosen Solution

are there other files involved?

There are. The files above are just the calendar data. But you'd need to have the correct calendar definitions as well. This is part of prefs.js in your profile folder. I strongly advice not to mess with prefs.js manually, unless you know exactly what you're doing. So your best bet is to re-create the calendar exactly the way it was before the incident, even if it's empty at that point.

In the calendar-data folder I see two files. deleted.sqlite which is from the day before the calendar was deleted and local.sqlite which is quite a bit larger. Could that file simply be replaced from the prior nights backup

Once you have the calendar definition right, you can try to replace the files from the backup. I'd probably replace both files from the backup. Whether this works, I don't know. You'll have to give it a try. Make sure Thunderbird is closed when doing this.

Also create a full backup of your Thunderbird profile before you start messing with it. https://support.mozilla.org/kb/profiles-where-thunderbird-stores-user-data#w_backing-up-a-profile

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Replacing just the two calendar files did not work but I was able to replace the entire profile from the night before and that did work. Thanks for all your help!