I formatted my computer.

Before formatting, I copied dropbox folder to an external drive.

After formatting, I installed dropbox, linked to my account, stopped sync and pasted all the content inside old dropbox folder to new one. Now, the dropbox folder look same as it was before format.

However, after I started sync, it began to download all files one by one. Now it's saying like downloading XX.XXX files X hours remaining.

So, why doesn't it just understand these files already there and there is no need to download again? What could be problem?

1 Answer 1


Because, you broke the chain of trust. It doesn't know those files are the same, and simply sees your computer as a new system, since it got formatted.

It doesn't know which version is correct, so it does the logical thing (in its mind) and downloads the full fileset from the Dropbox Servers (which should always be up to date).

If you want to limit which folders to sync, you can right-click on the icon in the System Tray (I assume you're using Windows - You don't specify), go to the Settings icon, and choose the second tab. You'll see a button to Sync Selected Folders (wording may be off - It's not installed on this PC). A folder dialog will pop up, and list all the folders with checkmarks. Any folder with a checkmark will be synchronized automatically.

  • Thanks for your answer, I checked that too. All is checked though. Seems like I have to wait for a full sync. Jun 25, 2014 at 21:18
  • Unfortunately, yes. It's the only way Dropbox knows it's the correct file. Jun 25, 2014 at 21:23
  • I wonder if it would be better to not have the files in the dropbox folder at all, and let dropbox just download them all. It may feel the need to COMPARE the local files, slowing it way down.
    – Engineer
    Aug 26, 2015 at 22:39
  • 2
    @sitenook I'm pretty sure it only does a checksum to make sure existing files are right... At least I hope so. Dropbox also tends to ask for an empty folder to sync with, for this reason Aug 27, 2015 at 2:32
  • 2
    @CanadianLuke this is the correct answer. If an existing file name matches an online one it hashes the local file and decides if one needs updating to match the other (depending on which one is newer), or if the hashes match. The “downloading X files...” in this case is a red herring.
    – Darren
    Dec 17, 2017 at 18:31

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