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Hi

Im new to this, just got a LG blu ray external drive for mac and having problems backing up and ripping blu rays, here is the issue im having backing up avatar

MakeMKV v1.6.16 darwin(x86-release) started
Optical drive "DVD+R-DL HL-DT-ST DVDRW GS23N SB03" opened in DASPI v1.3 mode.
Optical drive "BD-RE HL-DT-ST BD-RE BE12LU30 4261" opened in DASPI v1.3 mode.
Backing up disc into folder "/Users/paulphillips77/Movies/backup/RED_BIRD_3D_WW"
Loaded content hash table, will verify integrity of M2TS files.
Error 'Scsi error - NOT READY:CANNOT READ MEDIUM - INCOMPATIBLE FORMAT' occurred while reading 'BD-RE HL-DT-ST BD-RE BE12LU30 4261' at offset '25020934144'
Backup failed

I am also getting this error when trying to rip to mkv

Error 'Scsi error - NOT READY:CANNOT READ MEDIUM - INCOMPATIBLE FORMAT' occurred while reading '/BDMV/STREAM/00001.m2ts' at offset '16756236288'
Error 'Scsi error - NOT READY:CANNOT READ MEDIUM - INCOMPATIBLE FORMAT' occurred while reading '/BDMV/STREAM/00001.m2ts' at offset '16756236288'
Failed to save title 2 to file /Users/paulphillips77/Movies/Avatar/title02.mkv
1 titles saved, 2 failed

This is a physical disc error - http://www.makemkv.com/faq/item/7/catid/6