Since Dropbox does not allow it’s folder to be located on external memory like USB stick or SD card, you will need to create symbolic link in Windows command prompt.
You will need to create symlink to point from your HDD location to your external memory.
First you need to start cmd.exe. Go to Start > “Search programs and files” and type cmd:
On resulting cmd.exe you will need to right click and select “Run as Administrator”:
There are different types of links you can create: soft link to file or directory, hard link to file or directory. In directory case it is often referred to as junction.
Soft link to file:
mklink YourLink YourFile
Soft link to directory:
mklink /D YourLink YourDirectory
Hard link to file:
mklink /H YourHardLink Your File
Hard link to directory (junction):
mklink /J YourJunction YourDirectory
In my case this is what I did to link “D:\Dropbox” to “E:\Dropbox” directory:
Be aware if you are more used to Unix/Linux directory structures that you replace slash “/” with backslash “\” in Windows.