Dropbox Not Syncing on Mac? Here's What to Check

You drag a 500 MB video into your Dropbox folder, and it just sits there with the blue “syncing” badge. Hours later, your iPhone Dropbox app still doesn’t show it. Or worse, files synced fine yesterday and today the menu bar icon shows a red X with “Can’t sync (insufficient permissions).”

Dropbox migrated from a custom kernel extension to Apple’s File Provider framework in 2022, which made things faster but introduced a new class of sync issues. Here’s how to diagnose and fix Dropbox on macOS Sonoma 14 and Sequoia 15.

Step 1: Check the Dropbox menu bar icon

Click the Dropbox icon in the menu bar. What it shows:

• Solid blue with checkmark: synced.
• Spinning circle: syncing now.
• Red X: error — click for details.
• Pause icon: manually paused.
• Yellow !: warning, sometimes a permission issue.

If you see a red X, hover or click for the specific error. The error message is your first real clue.

Step 2: Sign out and back in

Dropbox menu → avatar → Settings → Account → Sign Out. Quit Dropbox. Relaunch from Applications. Sign back in.

This clears auth tokens and triggers a fresh handshake. If your account had a security challenge that wasn’t acknowledged (an unusual login alert that needed approval, an MFA prompt that timed out), this resolves it.

Step 3: Check disk space

Dropbox needs free local disk to download. With Smart Sync (Online-only) enabled, it needs less, but never zero.

Apple menu → About This Mac → More Info → Storage Settings. If you’re under 10% free, free up space.

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Step 4: Restart Dropbox

Click Dropbox icon → avatar → Quit Dropbox. Wait, then relaunch.

If Quit Dropbox doesn’t actually quit (the icon stays in the menu bar), force quit:

killall Dropbox
killall "Dropbox Helper"

Then relaunch.

Step 5: Check the File Provider extension

Dropbox uses Apple’s File Provider on modern macOS. Confirm it’s loaded:

pluginkit -m | grep -i dropbox

You should see entries for com.dropbox.client.fileprovider or similar.

If not, Dropbox can’t sync. Reinstall the latest Dropbox client to register the extension fresh.

Step 6: Check for permission errors

If Dropbox shows “insufficient permissions” or “can’t access this folder,” macOS file permissions on the Dropbox folder are wrong. Fix:

sudo chown -R $(whoami) ~/Dropbox

(If you’ve moved Dropbox somewhere else, use that path.)

Or in Finder: select the Dropbox folder → File menu → Get Info → Sharing & Permissions → click the lock to authenticate → make sure your username has Read & Write → click the gear → “Apply to enclosed items.”

Step 7: Check for Selective Sync exclusions

Dropbox menu → avatar → Settings → Sync → Selective Sync. If folders you expect to be syncing are unchecked, Dropbox isn’t syncing them.

Check them, click Update, and Dropbox starts downloading.

Step 8: Check for unsupported characters or paths

Dropbox rejects file names with:

/ \ : * ? " < > |

And paths longer than 260 characters total.

Dropbox menu shows a “Can’t sync” item that lists the offending files. Rename them or move them out of Dropbox.

Step 9: Reset Dropbox database

If the local sync database is corrupted, sync silently fails. Reset it:

1. Quit Dropbox completely (killall Dropbox).
2. Open Terminal:

mv ~/.dropbox ~/.dropbox.backup
mv ~/Library/Application\ Support/Dropbox ~/Library/Application\ Support/Dropbox.backup

3. Relaunch Dropbox. Sign in. The local database rebuilds.

Your actual files stay where they are; this only nukes Dropbox’s local index.

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Step 10: Check for File Provider extension conflicts

If you also use OneDrive, Google Drive, iCloud, and Box, all of them register File Provider extensions. Stale ones from uninstalled apps can interfere:

pluginkit -m | grep -i fileprovider

Look for extensions from apps you don’t have anymore. The cleanup is to fully uninstall the parent app — drag-to-trash doesn’t remove extensions, but a proper uninstall does. Sweep’s app uninstaller handles this automatically.

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Step 11: Check for VPN / network restrictions

A VPN can block Dropbox endpoints, especially corporate VPNs with strict outbound filtering.

Test from Terminal:

curl -I https://www.dropbox.com
curl -I https://api.dropboxapi.com

Both should return 200 OK or 301/302. If they timeout, your network is blocking Dropbox.

Disconnect VPN. If Dropbox works VPN-off and fails VPN-on, configure split-tunneling or contact your IT admin.

Even with no active VPN, leftover extensions from old VPN apps block Dropbox. Check systemextensionsctl list and remove any old ones.

Step 12: Check Dropbox quota

Open dropbox.com in a browser → top-right avatar → “Manage account.” If you’re at 100%, uploads silently fail.

Free space by deleting large files, removing old shared folders, or upgrade your plan.

Step 13: Check for files locked by other apps

If a file is open in another app (Word, Excel, video editor), Dropbox sometimes can’t write the synced version. This shows as “Can’t sync — locked by another process.”

Quit the app holding the file. Sync resumes.

Step 14: Update Dropbox and macOS

Old Dropbox clients have known issues:

• Dropbox 175+ on macOS 14+ is required for stable File Provider integration.
• macOS 14.4 fixed File Provider regressions that affected Dropbox.
• macOS 15.1 fixed sync conflicts in File Provider.

Update both. Dropbox menu → avatar → Help → Check for Updates. macOS via Software Update.

Step 15: Reinstall Dropbox

If nothing else works, do a clean reinstall:

1. Quit Dropbox.
2. Drag Dropbox.app to the Trash.
3. Empty Trash.
4. Run a clean uninstall (the Dropbox folder of files stays; only the app and its caches go).

Then download a fresh Dropbox client from dropbox.com and install. Sign in.

This is where Sweep’s uninstaller comes in handy: a full Dropbox uninstall has launch agents in ~/Library/LaunchAgents/, app data in ~/Library/Application Support/Dropbox/, the File Provider extension, login items, and the actual app. Sweep removes all of those at once.

When Dropbox is just slow

Some realities about Dropbox on Mac:

• The first sync after sign-in is slow — sometimes hours for a large account.
• Large numbers of small files (hundreds of thousands) sync slowly.
• Files larger than 50 GB don’t sync via the desktop client at all.
• Sync pauses on battery if you don’t disable that in Settings → Sync → “Sync data on battery.”

Most “Dropbox not syncing” cases are fixed by Step 4 (restart), Step 9 (database reset), or Step 10 (File Provider cleanup). If you’ve worked through this guide and Dropbox still won’t sync, contact Dropbox support — they have account-side tools that can clear locks the desktop client can’t reach.