Dropbox is an amazing cloud based file syncing tool available for Windows and all platforms. You can easily sync files between your system and cloud using Dropbox, but what was lacking in Dropbox is a portable version which can be used from a USB drive. DropboxPortableAHK is a nice freeware tool which makes your Dropbox installation portable and you can access it anywhere using a USB drive. Once you download and launch DropboxPortableAHK, it will download the latest Dropbox files required to your PC, you can specify the folder where you want it to be downloaded.
Once it downloads all the files, you can either create a Dropbox account or login to your existing account.
Once you login to your account, it actually syncs all the current folders available in your account to folder where your portable Dropbox files are available. Once the sync is complete, you can see all your Dropbox files inside this portable installation. You can now copy the complete folders to your USB drive and sync it with any computer without having to install Dropbox.
This portable version is very much useful when you do not have permission to install software on your PC. You can select which folders should be synchronized to your folder (Selective Sync) and also you can maintain multiple Dropbox accounts on the same computer/user account.
Download Dropbox Portable [Via GHacks