Prevent Dropbox, Google Drive, Skydrive, files resyncing when reinstall operating system

I currently use Dropbox, Google Drive, Microsoft Skydrive. They reside in these folders:

C:\users\fortune\dropbox
C:\users\fortune\SkyDrive
C:\users\fortune\Google Drive

First, I need to move them to another drive (D:). I plan to follow these instructions. Dropbox & Google Drive, SkyDrive move instructions.

Assuming the the move is successful, my question now is that I need to reinstall my Windows OS on C:. After I reinstall the OS and reinstall Dropbox, Google Drive, Skydrive, how can I prevent them each from trying to redownload all my cloud-stored files, and also redundantly upload all my files from D:?

Before reinstalling them, create links using mklink, such that they appear to be in the right place.

The default locations will be automatically populated with your files after installation, and there should be no redundant uploading either.

Example, as requested:

Let's assume we're dealing with DropBox. This will apply to the others too, but for convenience I'll explain just the one.

• Stop DropBox from running (I think it is a Windows Service)
• Move the data from C:\Users\Fortune\DropBox to D:\Cloud\DropBox. Don't copy, because the folder on the C: drive must no longer exist for the next step to work correctly.
• Create a directory junction* with MKLINK /J C:\Users\Fortune\DropBox D:\Cloud\DropBox
• Check in Windows Explorer that the junction is there. It should behave like the real thing.
• Start DropBox again.

What happens is you fool your OS into thinking that the folder on the D: drive is where it always was.

When you then format the C: drive, the junction point goes away, your data is safe, and when you install DropBox again, you just recreate the junction point before installing it, to make sure it uses the existing data. No duplication or re-uploading required.

**(I've typed this edit on an iPad with no access to Windows, so I hope the MKLINK syntax is correct.)*