XPS 8900, no Device Encryption

I was looking to enable Device Encryption on my XPS 8900 and I didn't see that option available in the settings. After running MSINFO32 it showed the following line:

Device Encryption Support Reasons for failed automatic device encryption: Un-allowed DMA capable bus/device(s) detected

I'm not sure why it would give this error as nothing has changed hardware wise since it left the factory.