Slack advanced exporter and attachments

Has anyone had success exporting slack workspace attachments and successfully importing them all into a gitlab mattermost team?

We had tried suing the advanced exporter some time ago and successfully exported our files, but now the tool doesn’t seem to work - can anyone confirm that? I process our export archive for emails first, then for files, and nothing happens.

Any help and step by step instructions to complete would be very appreciated.

Hi @oscargoldman,

What Mattermost server version are you currently on? What error messages do you get when attempting to use the advanced exporter?

Mattermost Version 5.3.1
I don’t get any error message from the advanced exporter. The first step of getting user emails seems to work - the output archive is slightly bigger and the output in the terminal shows the emails that have been pulled from slack. the fetch-attachments function though seems to run silently, there’s no console output, it runs very quickly (too quickly), and the resulting archive is the same size as the input.
I believe when we successfully pulled our files back in June we had something like 10’s of GBs of files. I checked with slack support today and they say they are not aware of that tool or its workings (though I’m sure there used to be a link to the tool from their export page). They also confirmed that as far as they know, there’s no way to export file attachments from Slack. I’ve seen some posts related to mattermost and other slack alternatives where it seemed it was possible, but maybe Slack has blocked that now?

Hi @oscargoldman,

Looks like there is discussion about it here:, and somebody is working on a fix:

If the fix looks like it will work for you, I can ping our devs to review the PR and get it merged.

I was able to run the forked version and it did create an export archive file of around 30GB. But the mattermost import failed, only 4 of dozens of channels were imported and no posts on those channels had attachments.

Hi @oscargoldman,

We just opened a ticket to a related issue here:

The original report was here:

Thanks for the update - the import seemed to choke on pinned messages too. I can’t currently complete a slack import, and this is straight out of slack, with no attachments.