How to Fix Slack High Memory Usage on Windows

What Causes This?

Slack is built on Electron, which means it runs like a mini web browser on your PC. On Windows, high memory usage usually happens when Slack has been open for a long time, is connected to multiple workspaces, keeps a large local cache, or is loading lots of channels, messages, and shared files in the background. Browser-like apps can also spawn several background processes, which makes RAM usage look even higher in Task Manager.

Common Symptoms

• Slack uses several hundred MB or more in Task Manager
• Your PC feels slower when Slack is open
• Switching channels or workspaces becomes laggy
• Fans run more often or CPU and memory usage spike together
• Slack gets worse after being open for hours or days

How to Fix It Manually

1. Check how much memory Slack is using

   • Open Task Manager with Ctrl+Shift+Esc.
   • Click More details if Task Manager opens in compact view.
   • Under the Processes tab, find Slack and check the Memory column.
   • If you see multiple Slack processes, that is normal, but very high combined usage usually points to cache buildup or too many active sessions.

2. Fully quit and restart Slack

   • In Slack, click your profile picture in the top-right corner.
   • Choose Quit Slack. If it stays open, right-click the Slack icon in the system tray near the clock and select Quit.
   • Reopen Slack from the Start menu.
   • This clears temporary memory use and is often enough if Slack has been running for a long time.

3. Sign out of workspaces you do not need

   • In Slack, click your workspace icon or open the workspace switcher.
   • Sign out of unused workspaces, especially if you stay logged into several at once.
   • Each active workspace can add more channels, messages, and background syncing, which increases RAM usage.

4. Clear Slack’s cache

   • Open Slack.
   • Press Ctrl+, to open Settings, or click your profile picture > Preferences.
   • Look for options related to cache or troubleshooting. If available, use the option to clear cache or reset app data.
   • If you do not see that option, close Slack completely, then press Windows+R, type %appdata%, and press Enter.
   • Open the Slack folder and remove cache-related folders if present, then reopen Slack. Be aware that Slack may need to reload data afterward.

5. Disable unnecessary startup and background load

   • Open Task Manager with Ctrl+Shift+Esc and go to the Startup apps tab.
   • Find Slack, right-click it, and choose Disable if you do not need it launching with Windows.
   • In Slack settings, turn off nonessential features such as automatic media loading or extra notifications if available.
   • This reduces background activity and lowers memory pressure over time.

6. Update or reinstall Slack

   • In Slack, check for updates from the app menu if the option is available.
   • If memory use stays unusually high, uninstall Slack from Settings > Apps > Installed apps.
   • Restart your PC, then download and install the latest version of Slack.
   • A clean install can remove corrupted app data that keeps memory usage high.

Fix It Automatically with Kudu

Kudu can quickly identify apps like Slack that are using too much RAM and point out the background processes, startup items, and cached data contributing to the problem. Instead of digging through Task Manager and app folders yourself, Kudu helps you reduce memory usage faster and keep Windows running smoothly.

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