ThinApp User’s Guide : Configuring Package Parameters : Configuring Sandbox Storage and Inventory Names : SandboxRemovableDisk

The SandboxRemovableDisk parameter determines whether the application can write removable disk changes to the disks or to the sandbox. Removable disks include USB flash devices and removable hard drives.
ThinApp sets an initial value that instructs the application to write removable disk file changes to the disk.
To save space, you can modify the SandboxRemovableDisk parameter to direct removable disk changes to the sandbox. Depending on the isolation mode for the removable disk, changes to files stored on the disk can reside in the sandbox or on the removable disk.