I do not think that it is a surprise for anybody that working with Microsoft Teams and different organizations is a big hassle. The multi-tenant setup is not very user friendly yet. On the right top in Teams you can switch organizations, but that only works if you are signing in with the same username and password to another organization. In other words, your account needs to be added as a guest account to the Active Directory in the other organization.
For a lot of us, working as a consultant for different clients, this is not our day-to-day practice. We have a separate Microsoft account for every client, which requires signing out and signing in again. If case you have single sign-on enabled, it can become even a bigger struggle to sign in with a different account than your organization one. As a solution, you might be running Teams in a browser window, which is a first step, but it is still hard to keep up with everything that is happening in Teams.
Well… not for long. With the few little tricks I describe below, you can run multiple Teams environments at the same time by using the new Edge Chromium browser and also customize it so you directly see which Teams environment you opened.
I appreciate that Marc has a very useful workaround. I hate that Marc has to spend the time coming up with a workaround in the first place. I definitely prefer the Slack model, where it doesn’t matter which account I’m using—I see all of my workspaces in one go, regardless of the e-mail address I’ve used.