[Natobasso]

Have you repaired permissions on her machine?

Is she working on ID files on the external drives or on her machine directly? This can sometimes cause issues if she's working on files remotely. Make sure she has full Read/Write permissions on the hard drives. Sounds obvious, but sometimes this can get screwed up. Use TinkerTool to force her permissions to be Read/WRite, Read/Write and Read/Only for Other.

Could you describe her ID files in more detail? Does she have low res or high res previewing on? Are her images placed or embedded? And what font management app does she use?