now iTunes 12.5.3.17
Disk Utility (Yosemite version) reports errors after trying to back up iPod touch iOS 10.1.
2016-11-09 15:15:44 -0500: Verifying volume “MyBook_4HET”
2016-11-09 15:15:44 -0500: Starting verification tool:
2016-11-09 15:15:45 -0500: Verifying file system.
2016-11-09 15:15:45 -0500: Checking Journaled HFS Plus volume.
2016-11-09 15:15:45 -0500: Checking extents overflow file.
2016-11-09 15:15:46 -0500: Checking catalog file.
2016-11-09 15:15:46 -0500: Incorrect number of thread records
2016-11-09 15:15:54 -0500: Invalid leaf record count
2016-11-09 15:15:54 -0500: (It should be 17298 instead of 17305)
2016-11-09 15:15:54 -0500: Checking multi-linked files.
2016-11-09 15:15:54 -0500: Checking catalog hierarchy.
2016-11-09 15:15:54 -0500: Invalid directory item count
2016-11-09 15:15:54 -0500: (It should be 875 instead of 880)
2016-11-09 15:15:54 -0500: Invalid directory item count
2016-11-09 15:15:54 -0500: (It should be 0 instead of 4294967289)
2016-11-09 15:15:54 -0500: Checking extended attributes file.
2016-11-09 15:15:54 -0500: Incorrect number of extended attributes
2016-11-09 15:15:54 -0500: (It should be 2688 instead of 2690)
2016-11-09 15:16:03 -0500: Checking volume bitmap.
2016-11-09 15:16:03 -0500: Volume bitmap needs repair for under-allocation
2016-11-09 15:16:03 -0500: Checking volume information.
2016-11-09 15:16:03 -0500: Invalid volume free block count
2016-11-09 15:16:03 -0500: (It should be 114044055 instead of 114044088)
2016-11-09 15:16:03 -0500: The volume MyBook_4HET was found corrupt and needs to be repaired.
2016-11-09 15:16:03 -0500: File system check exit code is 8.
2016-11-09 15:16:25 -0500: Error: This disk needs to be repaired. Click Repair Disk.
2016-11-09 15:16:25 -0500:
2016-11-09 15:16:25 -0500: Disk Utility stopped verifying “MyBook_4HET”: This disk needs to be repaired. Click Repair Disk.
The volume repairs OK