Application Support Folder Is Huge: What's Safe to Delete?

Don't delete it directlyDiskmack safety tier: System managed

~/Library/Application Support

Don't delete the Application Support folder itself. It holds the working data your apps depend on: settings, local databases, chat history, licenses, saved projects. Wipe it and most of your apps behave like a fresh install, and some of that data is gone for good. The right move is to find which app's subfolder is eating the space and deal with that one app.

What it is

~/Library/Application Support is where Mac apps keep everything that isn't the app itself. The .app bundle goes in /Applications, but most of an app's state lives here: internal databases, downloaded content, plugins, anything it needs to remember between launches. (Classic preference plists sit next door in ~/Library/Preferences, though plenty of apps keep settings here too.) Most apps you've run have a subfolder in it, usually named after the app or its developer. Sandboxed Mac App Store apps are the exception: they keep their version of this folder inside ~/Library/Containers instead.

It grows huge because it's a mixed bag. Some contents are genuinely disposable caches (Chromium-based apps such as Slack, Discord, and Spotify stash hundreds of megabytes of cache data inside their subfolders here). Some contents are real data you'd hate to lose: your iPhone backups live in the MobileSync subfolder, Steam keeps installed games under its subfolder, and many apps store your actual documents and project files here. That's why the folder can quietly reach 20, 50, or 100 GB or more, and why you have to drill in before judging any of it.

Is it safe to delete?

Not as a whole. Deleting the entire folder signs you out of most of your apps, resets their settings, and destroys data that has no other copy: message history, app licenses, local project files, iPhone backups. macOS won't stop you from trashing it, which is exactly why people get burned. Treat the top-level folder as off limits and make your decisions one subfolder at a time.

Individual subfolders are a different story. If a subfolder belongs to an app you've uninstalled and won't reinstall, it's usually dead weight and safe to trash, though peek inside first in case the app stored documents there. For apps you still use, leave their subfolder alone and clear space through the app's own settings instead. Diskmack maps each subfolder in Application Support to its app and flags which ones are leftovers from uninstalled software, so you're not guessing from cryptic folder names.

How to check its size

In Finder: In Finder, choose Go > Go to Folder (or press Command-Shift-G), enter ~/Library/Application Support and press Return. To see the total size, go up one level to ~/Library, click once on Application Support, and press Command-I. Inside the folder, switch to List view and enable View > Show View Options > Calculate all sizes so you can sort subfolders by size.

In Terminal:

du -sh ~/Library/"Application Support"

Keep the tilde outside the quotes so it expands to your home folder. For a per-app breakdown, run: du -sh ~/Library/"Application Support"/* | sort -rh | head -20.

How to clean it

In Finder, choose Go > Go to Folder and enter ~/Library/Application Support.
Switch to List view, open View > Show View Options, and check Calculate all sizes. Then sort the window by Size.
Work down from the biggest subfolders and match each name to an app. Most are obvious; search the web for any name you don't recognize before touching it.
If a subfolder belongs to an app you've deleted and won't reinstall, open it to confirm it holds no documents you need, then drag it to the Trash.
For apps you still use, don't trash their subfolder. Clear space from inside the app instead: Slack has Clear Cache and Restart under Help > Troubleshooting, and Spotify has a Clear cache button under Settings > Storage. Discord has no such button, so quit it fully, then trash only the Cache, Code Cache, and GPUCache folders inside its discord subfolder.
Empty the Trash, then re-check the folder size to see what you got back.

Some names don't match the app that made them. MobileSync is your iPhone and iPad backups, so leave it alone unless you've confirmed you don't need those backups. When in doubt, look the folder name up first.

Will it come back?

The folder itself always comes back; macOS and your apps recreate their subfolders on next launch. Whether the size comes back depends on what was using the space. Cache-heavy apps like Slack or Spotify will regrow their data within weeks of normal use. Subfolders you removed for uninstalled apps stay gone. If iPhone backups were the culprit, the space returns the next time you back up a device to this Mac. Expect to repeat the per-app cleanup a few times a year rather than treating it as a one-time fix.

Common questions

Can I just delete the whole Application Support folder to free space?

No. You'd reset every app on your Mac and permanently lose anything stored only there: message history, licenses, local databases, iPhone backups. Some apps would also break until reinstalled. Always work at the subfolder level.

Why is Application Support bigger than my Applications folder?

App bundles in /Applications are mostly just the program code. The data those apps accumulate (caches, media, backups, game files, databases) lands in Application Support, and data grows while code doesn't. A 200 MB app can easily sit on 10 GB of support data.

There's a MobileSync folder in here taking tens of gigabytes. What is it?

Those are local backups of your iPhone or iPad, stored at ~/Library/Application Support/MobileSync/Backup. Manage them from System Settings > General > Storage (look for iOS Files) or from the device's Finder page rather than deleting the folder by hand, and keep at least one recent backup per device.

Is it safe to delete a subfolder for an app I've already uninstalled?

Usually, yes. Check inside first for documents or exports you might want, and remember that if you ever reinstall the app you'll start from default settings. If the folder name doesn't clearly match an app you removed, identify it before trashing it.