How to Clear Slack Cache on Mac and Reclaim Gigabytes

If Slack has been running on your Mac for more than a few months, it is almost certainly hoarding hundreds of megabytes — sometimes over a gigabyte — of cached images, service-worker data, and code artifacts you never asked it to keep. This guide shows you exactly how to clear Slack cache on Mac using the built-in app reset and manual Terminal cleanup, what is safe to delete, and what to leave alone.

Why Slack Takes Up So Much Space on Mac

Slack on macOS is built on Electron, a framework that bundles a full Chromium browser engine inside the app. That engine behaves exactly like Chrome: it caches network responses, service-worker payloads, JavaScript bundles, GPU shaders, and IndexedDB data — all of it stored in ~/Library/Application Support/Slack/. Each workspace you join adds to this pile, and nothing prunes it automatically.

On a real Mac running Slack across two workspaces for several months, the breakdown looks roughly like this:

The service-worker cache is the biggest offender. Slack registers a service worker that intercepts and caches almost every network request so the app works offline — useful in theory, but it accumulates without a size ceiling.

Method 1: Clear Slack Cache from Inside the App

Slack has a hidden developer menu that lets you clear storage without touching Terminal. This is the safest starting point because Slack handles it gracefully and you stay logged in.

1. Open Slack and make sure it is the focused application.
2. In the menu bar, click Help. If you do not see a Troubleshooting submenu, hold Option while clicking Help — the extra entries appear only when Option is held.
3. Choose Troubleshooting → Clear Cache and Restart.
4. Slack will quit, wipe its HTTP cache, and relaunch. Sign-in state and preferences are preserved.

What this clears: The Chromium HTTP cache and some temporary data.
What it does NOT clear: Service-worker storage, Code Cache, GPUCache, IndexedDB, or logs. For a deeper clean you need the manual steps below.

Method 2: Manual Cache Cleanup via Terminal

This removes the bulk of the storage — especially the service-worker cache — that the in-app reset leaves behind. Quit Slack completely before running any of these commands. Deleting files while Slack is running can corrupt its internal database.

Step 1: Quit Slack

1. Right-click the Slack icon in the Dock and choose Quit, or press Command + Q with Slack focused.
2. Verify it is gone from the menu bar — Slack runs a background agent that can hold files open.

Step 2: Remove the safe-to-delete cache directories

Open Terminal (Applications → Utilities → Terminal) and run:

rm -rf ~/Library/Application\ Support/Slack/Cache
rm -rf ~/Library/Application\ Support/Slack/Code\ Cache
rm -rf ~/Library/Application\ Support/Slack/GPUCache
rm -rf ~/Library/Application\ Support/Slack/Service\ Worker/CacheStorage
rm -rf ~/Library/Application\ Support/Slack/logs
rm -rf ~/Library/Application\ Support/Slack/DawnGraphiteCache
rm -rf ~/Library/Application\ Support/Slack/DawnWebGPUCache

Each of these is a pure cache — Slack regenerates them on the next launch. You will not lose messages, files, or workspace settings.

Step 3: Relaunch Slack

Open Slack normally. The first load after a cache clear takes a few extra seconds as it re-downloads the service worker and primes its caches. Everything will look and work exactly as before.

What Is Safe to Delete vs. What to Leave Alone

• Safe to delete: Cache, Code Cache, GPUCache, Service Worker/CacheStorage, logs, DawnGraphiteCache, DawnWebGPUCache
• Leave alone: IndexedDB (stores local message history and search index), Local Storage (preferences), Cookies (session tokens — deleting this logs you out of every workspace), Preferences, local-settings.json

Deleting IndexedDB or Local Storage will not break Slack permanently — it will re-sync from Slack's servers — but you will lose your local message cache and may be signed out. Only do this if you are troubleshooting a corrupted installation, not just reclaiming space.

Slack Cache Location on Mac: Full Path Reference

All Slack data lives under one root path for the Mac App Store version and the direct download version alike:

~/Library/Application Support/Slack/

The tilde (~) is shorthand for your home folder. To open it in Finder without Terminal, press Command + Shift + G in any Finder window and paste the path above.

There is also a small HTTP storage entry at:

~/Library/HTTPStorages/com.tinyspeck.slackmacgap

This is usually only a few hundred kilobytes and can be deleted safely if Slack is quit.

How Often Should You Clear Slack's Cache?

There is no universal rule, but a practical guideline: if Slack is consuming more than 500 MB and you are not actively troubleshooting offline functionality, a cache clear is reasonable. For heavy users who are in many channels with lots of file sharing, doing this every three to six months keeps storage from compounding.

If you want a quicker way to catch this without memorising paths, Crumb — a native macOS disk cleaner — will surface Slack's cache containers in its Uninstall / leftover scan. Electron apps like Slack are known for leaving large cache directories behind, and Crumb's leftover finder catches exactly these kinds of containers so you can review and remove them without opening Terminal. Its "Is this safe to delete?" AI can also explain any unfamiliar Slack subdirectory before you commit.

Preventing Slack from Bloating Again

• Limit connected workspaces. Each additional workspace multiplies service-worker cache size. Leave workspaces you no longer use actively.
• Do not keep Slack open 24/7 if you do not need it. The cache grows with usage — it is not purely time-based.
• Check periodically. Run du -sh ~/Library/Application\ Support/Slack/ in Terminal every few months to keep an eye on total size.
• Use the in-app clear first. It is fast and safe; follow up with the manual steps only when the size warrants it.

Conclusion

Clearing Slack's cache on Mac is straightforward once you know where to look. The in-app reset under Help → Troubleshooting handles everyday buildup, while the Terminal commands above go deeper and reclaim the service-worker storage that causes most of the bloat. Stick to the safe-to-delete list, quit Slack before touching any files, and you will get your gigabytes back without losing a single message or preference. If you want a one-stop tool that flags this automatically alongside other disk hogs, you can download Crumb and let its leftover scanner do the hunting.