L700 library with 6 Seagate Ultrium 06242 LTO1 drives, 2 of which are SCSI attached direct to a NetApps filer. Backup s/w is NetBackup DataCenter 4.5(MP5) Tape drive and library firmware recently updated by Storagetek. All drives to firmware level 1613; Library to 0307. No problems until new media in barcode range 001220 - 001244 loaded. Now NDMP drives reject any barcode from 001220 onwards. Robot hand loads and immediately unloads tape and errors show as ndmp rewind fails and MEDIUM NOT PRESENT. NetBackup error code is 83 media open error. Can load manually via robtest. Tapes are writeable, same cartridges and barcode labels as rest of the range, no problems on any of the 4 drives SCSI attached to the NetBackup Master (Solaris 8); NDMP backups are still OK on media below barcode 001220. Any ideas please?