If Veeam Backup & Replication attempts to load an LTO-9 tape that has not been initialized or has an unknown status in the library, the library will report the error

Source Not Ready error (SCSI Check Condition 05/4481).

Error [MT]SCSI PASS THROUGH DIRECT ended with Scsi Error Fixed format, current;  Sense key: Illegal Request. ASC= 0x0000000000000044, vendor specific qualification ASCQ=0x0000000000000081

According to the User Guides for HPE MSL2024 and 1/8 G2 Autoloader, these tape libraries do not support tape media movement during the LTO9 initialization process.  

This results in the abovementioned error message when trying to run inventory for brand-new LTO9 tapes that have not been initialized yet. Preventing the movement of uninitialized or unknown status LTO-9 media ensures that such tapes are not loaded into the drive accidentally and thus helps to avoid possible timeout issues and backup delays while a new LTO-9 tape initialization is in progress.

Per LTO FAQ: Media optimization averages 20 minutes per first load of a cartridge to a tape drive. Although most optimizations will complete within 30 minutes, some optimization may take up to 2 hours.