This message was posted on behalf of Intel Corporation
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The change from MBR to GPT should not affect that the Intel controller recognizes the drives, but I would recommend verifying with your OS manufacturer if that change may affect your operating system (if you have any installed).
In your RAID 10 built, if you change one drive ( from 1 TB to 4 TB) what is going to happen is that the RAID will start a rebuilt process, bear in mind that you can change only one disk at the time, and then you have to wait for the rebuilt to complete before making any other change.
Our recommendation is to have all the information on your system back up before making any change to avoid any data loss.