1. Create a folder C:\My Dropbox Flash Drive
2. Open Windows “Computer Management” and under Storage, click on Disk Management.
3. Right-click on the SD Card and select Change Drive Letter and Paths
4. Click Add button
5. In the Add a new drive letter or path for YOUR USB flash drive: select the radio Mount in the following empty NTFS folder
6. Click Browse button… and navigate to the directory that you created
7. In Dropbox Preferences, select the C:\My Dropbox Flash Drive