I could manage to resize the system partition by using a third party utility software but think there must be more efficient way to do it. Here's how I did it: 1. I let the Surface 3 Pro boot from a USB bootable drive for the third party utility. 2. Noted that I could not resize the OS drive or any drive. 3. I disabled TPM and Secure Boot Control on UEFI. 4. Surface 3 Pro did not boot and instead got to recovery mode asking for recovery info. 5. I could not find the info anywhere and I reset the Surface 3 Pro. 6. I launched the third party utility again and could resize the partition this time. BTW: I enabled TPM and Secure Boot Control and the drive can no longer be resized. Any suggestion or comment is appreciated.