I am not 100% certain, but I believe that you can manually move the cache around. You do need to stop the StableBit CloudDrive service before doing so (I'd recommend setting it's startup type to "disabled" and rebooting).
Once the data is moved over (it needs to be moved from root directory to root directory), you'd want to take the older disk offline (aka, remove it). And then you can start the StableBit CloudDrive Service. It *should* pick up the cache folder and allow you to continue using it.
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