Hello cbrun, What you will need to do is to flash the ML6000 firmware. With the ML6000 it uses the drives serial# to know which drives are in the system. Since you have changed the drive it is trying to do a firmware upgrade on the drive so it can bring it to the last level of the drive that was previous in the system. Also since you reduced your drive count from 2 drives to 1 you need to flash the library firmware so the correct element address table can be corrected. Here is a link to the firmware for your ML6000. [URL]   After you have flashed the library firmware you will need to go to the library and put the drive online. Here is how you can do it from the web utility or from the front panel.  Please let us know if you have any other questions.
Changed from two LTO-4 drives to a single LTO-5 drive.  I put the LTO-5 drive in the control slot (0,2).  It will not come online.  Under the troubleshooting, I get: Resolve Tape Drive Type Change Troubleshooting Steps: Remove the original drive from the partition's configuration, then add the new drive to the partition's configuration per steps 1 and 2 below: 1) From the Main Menu select Setup->Partitions. From the Setup-> Partitions menu, choose the partition to be modified and select 'Modify'. From the Modify Partition menu, deselect the original drive from the drives list and select 'Apply'. 2) From the Setup->Partitions menu, choose the partition to be modified and select 'Modify'. From the Modify Partition menu, select the new drive from the drives list and select 'Apply'. However, drives hosting the control path for this partition are not selectable and cannot be deleted. I do not know what my next step should be.
ML6000 Changed both drives to LTO5