Symptom:

• Able to see USB hard drive content but unable to write to USB hard drive connected to router's ReadySHARE port from Mac computer.
• Error that says  "The iTunes application could not be opened. Unknown error 13008"

Cause:

Apple uses a file system called HFS+. To read and write to the ReadySHARE USB hard drive, the router need to support HFS+.

• R7000, WNDR4700/4720, WNDR4500, WNDR4300, WNDR3800, WNDRMACv2 supports HFS+ read and write.  
• Other NETGEAR home routers only support HFS+ read format which only allows you to see the USB content but not write to it.

Resolution:

1. Use WNDR4700/4720, WNDR4500, WNDR4300, WNDR3800, WNDRMACv2 if HFS+ and Time Machine support is required.
2. Convert/format file system to NTFS, FAT32, or EXT file format to be able to read and write to USB hard drive when using iTunes.