What causes "Dropbox Using Too Much CPU or Memory"?

Initial or very large sync Antivirus, security or backup software reading the Dropbox folder Files with wrong permissions that Dropbox keeps retrying Dropbox folder on a NAS (unsupported) File system without extended attribute support 300,000+ synced files

How do I fix "Dropbox Using Too Much CPU or Memory"?

1. Let the first sync finish: High CPU right after install or adding big folders is expected Leave the computer on and connected until the icon shows up to date 2. Use selective sync or online-only files: Dropbox icon > avatar > Preferences > Sync > Selective Sync Untick large archive folders, or right-click them > Make online-only 3. Find conflicting software: Temporarily quit antivirus/backup apps one at a time If CPU drops, add the Dropbox folder to that tool's exclusions 4. Fix file permissions: Give your user full read/write permission on the Dropbox folder If you see 'Permissions have been denied' or 'rejected by the server', contact Dropbox support 5. Move the Dropbox folder off a NAS: Preferences > Sync > Dropbox folder location > Move Choose a local internal or directly connected external drive

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Dropbox Using Too Much CPU or Memory

Workaround available Windows, macOS, Linux Updated October 21, 2026

Quick answer

Dropbox uses high CPU during big syncs or when antivirus/backup apps keep touching files, and RAM grows with file count (performance drops around 300,000 files). Reduce synced files and exclude Dropbox from scanners.

Most likely fix: Let the first sync finish.

Symptoms

Fans spin up, Dropbox appears at the top of Task Manager or Activity Monitor, laptops get hot or slow, Finder/File Explorer lags in the Dropbox folder.

Why it happens

Initial or very large sync
Antivirus, security or backup software reading the Dropbox folder
Files with wrong permissions that Dropbox keeps retrying
Dropbox folder on a NAS (unsupported)
File system without extended attribute support
300,000+ synced files

How to fix it

Try these in order — the most common fix is first.

1. Let the first sync finish
1. High CPU right after install or adding big folders is expected
2. Leave the computer on and connected until the icon shows up to date
2. Use selective sync or online-only files
1. Dropbox icon > avatar > Preferences > Sync > Selective Sync
2. Untick large archive folders, or right-click them > Make online-only
3. Find conflicting software
1. Temporarily quit antivirus/backup apps one at a time
2. If CPU drops, add the Dropbox folder to that tool's exclusions
4. Fix file permissions
1. Give your user full read/write permission on the Dropbox folder
2. If you see 'Permissions have been denied' or 'rejected by the server', contact Dropbox support
5. Move the Dropbox folder off a NAS
1. Preferences > Sync > Dropbox folder location > Move
2. Choose a local internal or directly connected external drive

This guide also covers

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