In 7.5 it doesn't happen everytime, at this point I would say 4 out of 5 clone 
operations it will error.  Looks like this in the daemon.raw file: 

42506 1/26/2009 12:19:43 AM  2 0 0 2172 2168 0 cpback nsrd media notice: Volume 
"BJK776L3" on device "\\.\Tape0": Block size is 32768 bytes not 131072 bytes. 
Verify the device configuration. Tape positioning by record is disabled. 
38758 1/26/2009 12:20:59 AM  2 0 0 2172 2168 0 cpback nsrd media warning: 
\\.\Tape1 writing: The request could not be performed because of an I/O device 
error.
42506 1/26/2009 12:20:59 AM  2 0 0 2172 2168 0 cpback nsrd media notice: LTO 
Ultrium-3 tape BJK743L3 on \\.\Tape1 is full 
42506 1/26/2009 12:20:59 AM  2 0 0 2172 2168 0 cpback nsrd media notice: LTO 
Ultrium-3 tape BJK743L3 used 30 GB of 400 GB capacity 

or 

67985 1/26/2009 12:24:51 AM  2 0 0 2464 2424 0 cpback nsrmmgd Loading volume 
`BJK759L3' from slot `21' into device `\\.\Tape1'. 
38752 1/26/2009 12:24:56 AM  2 0 0 2172 2168 0 cpback nsrd \\.\Tape1 Verify 
label operation in progress 
38752 1/26/2009 12:25:09 AM  2 0 0 2172 2168 0 cpback nsrd \\.\Tape1 Label 
operation in progress 
42506 1/26/2009 12:25:14 AM  2 0 0 2172 2168 0 cpback nsrd media info: LTO 
Ultrium-3 tape BJK759L3 will be over-written 
42506 1/26/2009 12:25:17 AM  2 0 0 2172 2168 0 cpback nsrd deleted media 
notice: Deleted volume: volid=4042055718, volname=BJK759L3, pool=CHIP Scratch 
Pool, location=Quantum Scalar 50 
12361 1/26/2009 12:25:24 AM  2 0 0 2172 2168 0 cpback nsrd [Jukebox `Quantum 
Scalar 50', operation # 5]. Finished with status: succeeded 
0 1/26/2009 12:25:26 AM  2 0 0 2816 2812 0 cpback nsrmmdbd              pools 
supported: CHIP Weekly Clone Pool; 
42504 1/26/2009 12:25:54 AM  2 0 0 2172 2168 0 cpback nsrd media event cleared: 
Waiting for 1 writable volume(s) to backup pool 'CHIP Weekly Clone Pool' 
tape(s) on cpback 
38718 1/26/2009 12:25:54 AM  0 0 2 2172 2168 0 cpback nsrd cpback:cloning 
session saving to pool 'CHIP Weekly Clone Pool' (BJK759L3)  
0 1/26/2009 12:26:10 AM  2 0 0 2816 2812 0 cpback nsrmmdbd              pools 
supported: CHIP Weekly Clone Pool; 
38758 1/26/2009 12:27:13 AM  2 0 0 2172 2168 0 cpback nsrd media warning: 
\\.\Tape0 reading: The request could not be performed because of an I/O device 
error.
38758 1/26/2009 12:30:45 AM  2 0 0 2172 2168 0 cpback nsrd media warning: 
\\.\Tape1 writing: The request could not be performed because of an I/O device 
error.
42506 1/26/2009 12:30:45 AM  2 0 0 2172 2168 0 cpback nsrd media notice: LTO 
Ultrium-3 tape BJK759L3 on \\.\Tape1 is full 
42506 1/26/2009 12:30:45 AM  2 0 0 2172 2168 0 cpback nsrd media notice: LTO 
Ultrium-3 tape BJK759L3 used 7215 MB of 400 GB capacity

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