Slack import fails to import existing user

I am trying to import a Slack team into Mattermost, but it fails to import any users that pre-exist in the Mattermost team. It errors out on that user and does not import any posts that the user had made in Slack.

Unable to import user: <example_user>

The short term fix is to do the importing with a user that is not associated with the Slack group. However, this is not convenient for users to self-manage their own teams since all users are authenticating with an LDAP server through their Gitlab account. Is there a fix for this username collision?

I am using Mattermost 2.1.0 as part of the Gitlab 8.6.1 Omnibus package.

1 Like

Hi @dwest,

Our Slack import is still in Beta, and that’s one of the issues we still need to fix (being tracked in Jira). The solution being considered is to let the administrator select an option when these collisions happen - for example, to append a number to the username, change the username, merge, or cancel/skip the user. Do you have any feedback on what would work best for you?

In terms of a work around - are you just looking to get the history imported from Slack, if people already have accounts authenticating with GitLab? One option might be to ask the user to change their username in Slack to be slightly different, so you can export the history + import it to Mattermost without the username collision.

Thanks for the quick reply @lfbrock. We are mainly looking to migrate our active conversations from Slack to Mattermost in order to continue work. Ideally, we would like to be able to map accounts in Slack to accounts we already have in Gitlab since the email addresses are exactly the same. So an option for merging accounts would be preferable. It also looks like the import is preventing users from logging in due to them containing the same email address. So even with an invite link it would say the following:

Galois Mattermost needs your help:
Team example-team already has a user with the email address attached to your gitlab account

So if we could do some sort of account merge, then that would be best. I can see use cases where changing the username from Slack would be appropriate as well, so I think giving the option as opposed to picking only one would make this a little more flexible.

Hi @lfbrock
Any update on improving the import process? Looks like the Jira ticket (or sub tickets) you referenced haven’t been updated in over a year.

Hey @cvillalvav,

We actually had a new set of tickets for Slack import! We now support merging users, as long as they have the same e-mail in both the respective Mattermost and Slack account.


That’s great news @yang! I see that is available in v3.5.0 will update soon and reattempt the import.

No problem @cvillalvav! Let me know if it works.

How is this merging supposed to work? I don’t have that option and setting two user accounts to have the same emai address is not allowed even when I am an admin.

Same problem here. Any workaround ?