We are unable to accept seed drives. It certainly sounds like a good idea: you ship us a hard drive full of your files and we add them to your account, saving the initial upload time. However, this won't work with the way SpiderOak ONE functions. With SpiderOak ONE your encryption keys are derived from your password, and you're the only person with access to your password, so only you have the keys. The SpiderOak ONE application encrypts your data before it is uploaded to our servers, to ensure your data is secure and protected before it even leaves your computer. This severely cuts down on the chance of someone being able to intercept your data as it is being transmitted.
This brings up another point: shipping us a hard drive of information is not only shipping us unencrypted data, but via an uncontrolled means of transport. There's no way to guarantee the security of your drive and thus your data when using a third party to ship it. And even if we were to trust a third party, we would have no way of encrypting your data once we got it.
Even though it will take longer, uploading it from your end ensures your data remains yours. Your data will be encrypted by your computer and uploaded to our servers, where it will live as a series of encrypted containers. Even if someone were to intercept it on the way to our servers, they would not be able to decrypt your data to make any use of it.