When converting your T3 and creating a mirror set (RAID 1) through Windows disk manager, unplugging and then plugging the T3 unit back in may cause the RAID configuration be lost.
This is purely Windows Dynamic Disk design issue and now hardware related.
If you have created a dynamic disk mirror set, you have then unplugged T3, and now have a broken mirror, you should still be able to access your data from the device. By using Storage Spaces, included in Windows 8 and later versions, to create a mirror set, you will not encounter this issue.
Note: Storage Spaces is unavailable on Windows 7.