The Problem:

I am trying to migrate user from Outlook 2003 to Mozilla Thunderbird w/ Lighting extension.

User kept important data stored as Tasks. While I can easily export Tasks from Outlook 2003 to it's default CSV format, I found so far no way to import the CSV into Lightning.

The Research:

So far I have found no out-of-the-box solution.

In fact, the only solution I can actually think of would be to manually prepare and inject CSV data into the SQLite database storing Lighting data (<profile_dir>\calendar-data\local.sqlite).

That solution needs quite a lot of work, though. The single task data is stored among several tables, I'd have to manually match columns, find some solution to recalculate date values etc.

Attempted solutions:

  1. Tried to export data from Outlook to .ics using Outport as @Randolph West suggested. When ordered to import that file, Lightning did nothing.
  2. Attempted to build an .ics myself, basing on a template task exported from Lightning (so that I could be sure the format itself is not an issue). Same result as with attempt #1.

The Question:

I am looking for some out-of-the-box solution, or at least a near one. A solution that could be comfortably used by some less-than-skilled users.

  • According to one guy, outport.sourceforge.net is what you'll need. – user3463 Oct 9 '13 at 18:29
  • 1
    No luck. I've exported .ics using Outport, ordered Lightning to import it and nothing happened. Also tried building an .ics based on template task exported from Lightning - didn't work either. It's like if Lighting cannot import task data that way. – Michał Sacharewicz Oct 9 '13 at 19:08

I've been looking at this and can't find an easy solution.

However, I plan to try the following steps tomorrow, unless someone has a reason why it won't work:


  1. Export all Outlook TASKS to csv
  2. Edit the csv to look like Lightning EVENTS
    (this will lose some data and looks like the most difficult step as Lightning is very fussy about importing csv's. I think all fields have to be quoted, and dates without centuries will appear in the 1900's if you aren't careful)
  3. Create a new calendar and import all the EVENTS
  4. Select all the EVENTS and convert them to TASKS
    (this involves reviewing all the entries manually, but is better than having to retype them all!)
  5. Select all the TASKS and move them to another calendar (if you don't want them in a separate calendar)

Anyone who knows this won't work, please let me know. Otherwise I'll report back if it is successful.


  • 1
    OK - worked successfully but needed a bit of work: a) Couldn't export the tasks from Outlook 2000, kept crashing. Could copy all the tasks from task view and paste into Excel. b) Needed a bit of work in Excel to get the correct format for date and time. IMPORTANT: the Lightning csv import expects mixed case "True" for "All day event" - it ignored it in upper case. c) Used Open Office Calc to convert .xls to .csv as the import needs quotes around everything. Hope this is useful to someone Mark – Mark Dec 9 '13 at 11:17

One workaround is as follows:

  1. Install and run Outport

  2. It will parse through the pst file hierarchy and will display Tasks folders as well. Select the folders you want to export

  3. In the Tasks format options chose Evolution Tasks

  4. After you export is complete you can find all your tasks as one *.ics file per your Outlook folder

  5. Import ics files one by one to Thunderbird by right-clicking the required Calendar and selecting Export Calendar

One caveat - any attachements in Tasks will be lost. You will need to reattach them manually. Still it's better than the solution offered above.

Second caveat - you may or may not need to have outlook installed at the time to run Outport. I have Outlook installed on my machine, so it was not an issue.

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