Dropbox Eating Your Disk Space? Use Selective Sync to Reclaim It

Dropbox has filled your hard drive because it downloads a full copy of every folder to your computer.

Why: By default the desktop app keeps a local copy of everything in your account. Selective Sync lets you uncheck folders you don’t need on this computer — they’re removed from the hard drive but stay safe on dropbox.com, so you reclaim space without deleting anything.

Fix 1: Unsync folders you don’t need with Selective Sync

This is the main fix — pick which folders live on this computer.

On Windows:

1. Click the Dropbox icon in the taskbar.
2. Click your avatar (photo or initials) in the bottom-left corner, then click Preferences.
3. Open the Sync tab.
4. Under Selective Sync, click Modify.
5. Uncheck any folder you don’t need stored locally (leave checked the ones you want on this computer).
6. Click Update.

On Mac:

1. Click the Dropbox icon in the menu bar, then your avatar → Preferences.
2. Open the Sync tab.
3. Under “Select folders to sync to this Mac,” click Modify.
4. Uncheck the folders you don’t need locally, then click Update.

Unchecked folders are removed from your hard drive immediately. To get one back later, return here and re-check it.

Fix 2: Understand what stays and what goes

Knowing the rules prevents accidentally “losing” files.

• Checked folder = saved to your hard drive and synced.
• Unchecked folder = removed from this computer’s hard drive, still stored on dropbox.com and on any other computer where you’ve kept it checked.
• You can only select folders, not individual files — so group small files into a folder if you want to unsync them.
• Selective Sync is per-computer. Unchecking a folder on your laptop doesn’t affect your desktop or phone.

Fix 3: Empty Cache and re-check your free space

After unsyncing, confirm the space actually came back.

1. Open your file manager and check the drive’s free space — it should rise within a minute or two of clicking Update.
2. If space looks off, the hidden Dropbox cache may be holding files. Open the .dropbox.cache folder inside your Dropbox folder and delete its contents (Dropbox rebuilds it automatically).
3. Restart the Dropbox app to finish clearing local copies.

FAQ

Will unsyncing a folder delete my files? No. The files stay on dropbox.com and on any other device where the folder is still checked. You can re-download them anytime by re-checking the folder.

Selective Sync won’t update or keeps reverting. Make sure the app isn’t mid-sync, then quit and reopen Dropbox and try again. A folder that’s open in another program can also block the change — close it first.

I want some files local and others online without unchecking whole folders. Selective Sync only works on folders. For finer control over disk space, Dropbox also offers online-only files that download on demand.

Sources: Dropbox Help — Selective sync overview