As the primary owner of a Slack work space, can I force join a private channel? Can I even see the list of private channels I am not a member of?
I want to create a new channel called "unity" in my work space. Apparently, it is taken. No one else knows about that channel thereby I am guessing an employee no longer working here has created it as a private channel making it inaccessible. If so, is there any way to retake control of that channel?
According to Slack,
"Workspace Owners and Admins can delete any channel they've joined, except for the
#generalchannel."
Unfortunately, the owner explicitly needs to be a member of the channel in order to delete it, and owners of Slack workspaces can only see the private channels that they are already a member of.
However, if you have an application integrated with your Slack channel using a workspace token, that app is able to access each of the private channels. Note that this is a legacy feature in Slack, and you can no longer create workspace tokens, though existing workspace tokens will still function.
If you do not have any existing workspace tokens, another option would be to run an export. As of May 2019, workspace owners can now request an export of all channel content and private messages, as needed and permitted by law.
Note that you also need to be on the Slack Plus plan (or higher) to export private channels using the automated tool; the Free and Standard plan can only export from public channels without explicit approval from Slack themselves.
*Workspace Owners on the Free and Standard plans must contact Slack and apply to export content from private channels and one to one and group direct messages. We will reject applications, unless Workspace Owners show in each instance (a) valid legal process, or (b) consent of members, or (c) a requirement or right under applicable laws in order to export data.
Outside of the above options, your only option is to contact Slack themselves.