The short answer
Yes. Rebuilt or re-downloaded automatically when needed.
What is it?
The same web cache as the direct-download Slack app, stored inside the sandbox container of the Mac App Store version: images, file previews, emoji and other workspace content.
What happens if you delete it?
Slack fetches the content again from its servers as you use it. Messages and files stay in Slack’s cloud.
How to remove it properly
Quit Slack, then move ~/Library/Containers/com.tinyspeck.slackmacgap/Data/Library/Application Support/Slack/Cache to the Trash, or use Help › Troubleshooting › Clear Cache and Restart in Slack.
Quit the app that uses it, then move it to the Trash. Empty the Trash when you’re sure.
How MoreRoom helps
MoreRoom recognises this item, shows its real size and when it was last used, and labels it “Safe to remove”. In the free version you can move it to the Trash in one click, with Undo; Pro collects every safe item at once.
Frequently asked questions
Is it safe to delete the Slack cache (App Store version)?
Yes. Rebuilt or re-downloaded automatically when needed. Slack fetches the content again from its servers as you use it. Messages and files stay in Slack’s cloud.
Will Slack cache (App Store version) come back after I delete it?
Yes. Slack fetches the content again from its servers as you use it. Messages and files stay in Slack’s cloud.
How do I remove Slack cache (App Store version) properly?
Quit Slack, then move ~/Library/Containers/com.tinyspeck.slackmacgap/Data/Library/Application Support/Slack/Cache to the Trash, or use Help › Troubleshooting › Clear Cache and Restart in Slack.