Cloud sync clients — Google Drive, Dropbox, and OneDrive — are invaluable for keeping files accessible everywhere, but each one quietly accumulates local cache, offline copies, and temporary data that can consume tens of gigabytes on your Mac's SSD without any obvious warning. If you've ever wondered why macOS reports "System Data" or "Other" ballooning even after you tidy your Downloads folder, a swollen Google Drive cache on your Mac (or its Dropbox or OneDrive equivalent) is often the culprit.
Why Cloud Sync Clients Store So Much Data Locally
Each major sync client has a different philosophy about what it keeps on disk:
- Google Drive (Drive for Desktop) uses a virtual file system by default, but any file you open or mark "Available offline" is fully downloaded. A metadata and chunk cache backs this up.
- Dropbox traditionally downloaded your entire account to disk. Even with Selective Sync or Smart Sync enabled, it maintains a local cache of recently-accessed blocks and deleted file history (for the "Extended Version History" add-on).
- OneDrive uses Files On-Demand on macOS, so files appear as placeholders — but the Personal Vault and any pinned folders are fully local. OneDrive also writes a sizable SQLite telemetry and sync-state database.
None of this is malicious — it makes sync faster and enables offline access. The problem is that the clients rarely clean up proactively, and macOS doesn't count this data against your iCloud quota, so it's invisible to most users.
Google Drive Cache on Mac: What Exists and What's Safe
Google Drive for Desktop stores data in two main locations:
~/Library/Application Support/Google/DriveFS/— the primary database, account metadata, and chunk cache. This folder commonly reaches 2–10 GB.~/Library/Caches/com.google.drivefs.find-apps/— a smaller helper cache.
How to safely clear the Google Drive cache
- Quit Google Drive from the menu bar icon: click it, then click the gear icon and choose Quit.
- Open Terminal and run:
This removes cached metadata only. Drive will rebuild it on next launch. Do not delete the entirerm -rf ~/Library/Application\ Support/Google/DriveFS/Metadata/DriveFSfolder — it contains your account credentials and offline content list. - Relaunch Google Drive. Expect a brief re-sync of metadata (a few minutes on a normal account).
What is not safe to delete: the content_cache subdirectory holds blocks of files you marked as "Available offline." Deleting it while Drive is running can cause corruption. Always quit the app first, and understand that you will need to re-download those files.
Dropbox Cache on Mac: The Hidden .dropbox.cache Folder
Dropbox maintains a hidden cache folder inside your Dropbox directory itself:
~/Dropbox/.dropbox.cache/— blocks of recently modified or deleted files, retained so Dropbox can recover them without a server round-trip. This can silently grow to several gigabytes.~/Library/Caches/com.dropbox.DropboxMacUpdate/— update installer packages.
How to clear the Dropbox cache
- Fully quit Dropbox from the system tray.
- In Terminal, run:
Therm -rf ~/Dropbox/.dropbox.cache/*.dropbox.cachefolder itself must stay; only its contents can be removed. - Relaunch Dropbox. The cache will rebuild incrementally as you use files — it will not immediately refill to the same size.
Dropbox documents this cache as safe to delete while the app is not running. However, if you use Dropbox's Extended Version History add-on, some of those cached blocks back your ability to recover deleted files locally. After clearing, recovery still works via the web, just more slowly.
OneDrive Storage on Mac: Databases and Pinned Files
OneDrive on macOS stores its sync engine state and logs here:
~/Library/Containers/com.microsoft.OneDrive-mac/— the main sandbox, including a sync state database that can reach 500 MB–1 GB on busy accounts.~/Library/Logs/OneDrive/— verbose diagnostic logs, often 200–600 MB.~/OneDrive/(or your named folder) — any file that is "always available" is stored here in full.
How to reclaim OneDrive storage
- Quit OneDrive from the menu bar.
- Clear old logs:
rm -rf ~/Library/Logs/OneDrive/* - In the OneDrive app preferences, review Files On-Demand and right-click any folder marked "Always keep on this device" that you don't need offline. Choose Free up space to convert it back to a cloud-only placeholder.
- Relaunch OneDrive.
Do not touch the Containers sandbox database directly — OneDrive does not support manual editing of its internal database, and doing so while the app expects a certain schema can prevent it from launching.
Quick Comparison: Cache Locations and Risk Level
| Client | Cache / Storage Path | Typical Size | Safe to Delete? |
|---|---|---|---|
| Google Drive | ~/Library/Application Support/Google/DriveFS/Metadata/ |
1–5 GB | Yes, with app quit |
| Google Drive | ~/Library/Application Support/Google/DriveFS/content_cache/ |
Varies (offline files) | Yes, but loses offline access |
| Dropbox | ~/Dropbox/.dropbox.cache/ |
1–10 GB | Yes, with app quit |
| Dropbox | ~/Library/Caches/com.dropbox.DropboxMacUpdate/ |
200–500 MB | Yes |
| OneDrive | ~/Library/Logs/OneDrive/ |
200–600 MB | Yes |
| OneDrive | ~/Library/Containers/com.microsoft.OneDrive-mac/ |
500 MB–1 GB | Do not delete manually |
| OneDrive | ~/OneDrive/ (pinned files) |
Varies | Use "Free up space" in-app |
Finding Oversized Sync Caches Without Hunting Manually
If you'd rather not memorize every path, Crumb's whole-Mac audit surfaces the largest directories on your system — including Application Support subfolders that sync clients use — ranked by size. It highlights anything that looks like a cache or temporary store so you can spot a 6 GB DriveFS folder in seconds rather than digging through Finder's hidden Library. Crumb does not automatically delete sync-client data (those folders contain credentials and state, not just disposable cache), but it tells you exactly what's there so you can act with the steps above. You can download Crumb and run the audit for free.
Ongoing Best Practices to Keep Sync Storage Under Control
- Audit "Available offline" and "Always keep on this device" settings quarterly. Each file you pin is a full local copy. Remove pins for files you rarely access offline.
- Use Selective Sync in Dropbox to exclude large shared folders (design assets, video libraries) from your local machine unless you actively need them.
- Prefer streaming access for large media. Google Drive lets you stream video files without downloading them in full — avoid opening large files in apps that force a local copy.
- Clear Dropbox cache every few months if your account frequently moves or renames large files. The cache accumulates old blocks aggressively in those scenarios.
- Monitor ~/Library/Logs periodically — both OneDrive and Drive for Desktop write diagnostic logs that are safe to clear and are never touched by macOS's own storage management.
Conclusion
Cloud sync clients are some of the most storage-hungry background processes on a Mac, yet their caches are almost entirely invisible to users. By understanding which paths each client uses, what is truly safe to remove, and how to use in-app tools like Files On-Demand and Selective Sync, you can reclaim multiple gigabytes without touching a single file you care about. The key rule: always quit the sync client before touching its cache directories, and use the application's own controls to manage offline content rather than deleting files from inside the sync folder directly.