I've done sudo snap install slack --classic and now have the Slack snap application (v. 4.1.2). When I run slack from the terminal, it opens the app, with the sign in button. Clicking this opens the Slack login page in my default browser (chromium, snap app v. 78.0.3904.108), where I successfully login.

The trouble is that it says, "Signing you in to Slack. You should be redirected in a few moments." Then, a pop-up appears: "Open xdg-open?" I select "xdg-open" (instead of "cancel") and then......nothing happens. The Slack snap app still shows the sign in page, while the browser thinks I've logged in and just says "Signing you in to Slack."

Is this because of sandboxing issues with the Chromium snap app? I'd love for my Slack (multiple workspaces) to be in a separate app, instead of being trapped in a browser tab, so any and all help resolving this would be greatly appreciated! And apologies if this is posted in the wrong place; I'd be keen to know anywhere else that might better fix this.

Other possibly relevant details:

  • Hardware: 2015 Macbook Pro 13" Retina
  • OS: LXLE 18.04
  • 2
    Same problem in my case. I've just openned redirection link from Firefox and then xdg-open shows an application list from where you can select slack application – José Valenzuela Sanz Jan 16 '20 at 15:41
  • This worked for me as well. – Gijs Jan 22 '20 at 7:32
  • @JoséValenzuelaSanz could you please elaborate on what you mean by "opened redirection link from Firefox and then xdg-open shows an application list"? and the actions you're doing? Thanks! – jaymullr Feb 13 '20 at 0:05
  • Issue is documented here on launchpad, and should be fixed via either: 1) A future release of snapd, or 2) The merge & release of this PR I'd really like to get this escalated at Canonical so it's fixed before 20.04 release (seems a real shame to Zoom launching broken in this new COVID-19 world), but not sure how to do that. – Troy Ready Apr 2 '20 at 23:12

Copy the link from the browser and run

xdg-open slack://...yourlink

in your terminal.

  • I can confirm it works on Fedora 32 as well. – Qortex Jul 13 '20 at 12:02

This is because snap does not allow you to use special url schemes like slack:// . So chrome tries to open it but it is blocked. If you use firefox from apt you don't have this error and it will work fine (even if you use slack from snap). The error shows in your syslog:

user-open error: Supplied URL scheme "slack" is not allowed

To login using chromium anyways, at the bottom the page says this:

App didn't open? Try again, or sign in to Slack for the browser.

Right click "Try again" select "Copy link address" and with that in your clipboard just go back to slack. Slack will see the url in your clipboard and log you in.

Note: The fact this works is a slack feature. This does not work for other applications like zoom, unless of course they have this feature build-in as well.


Add the x-scheme-handler to your mimeinfo.cache like so:

$ echo "x-scheme-handler/slack=slack.desktop;" >> ~/.local/share/applications/mimeinfo.cache

make sure you have a slack.desktop file either in /usr/share/applications/ or ~/.local/share/applications/

If you don't then try this.

$ slack=$(which slack); cat > ~/.local/share/applications/slack.desktop << ENDL
[Desktop Entry]
Comment=Slack Desktop
GenericName=Slack Client for Linux

then cat ~/.local/share/applications/slack.desktop and make sure Exec= points to slack.

If this doesn't work, try

$ sudo apt install inotify-tools
$ inotifywait -m ~/.local/share/applications/{slack.desktop,mimeinfo.cache}

and see if those files are being opened. If this is still failing just comment below with your issues and I'll come back and tell you next steps. It was pretty frustrating only finding wrong answers for this question on the internet, I know your pain.


Faced this issue on a snap install of Slack. Using Firefox rather than a Chromium-based browser did the trick.

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