I suppose it's possible there's a fault on the Mac's USB port, but somehow it seems unlikely. If it's talking about corrupted files, is it possible it's referring to the hard drive? The reason I have a Mac on my desk is because the disk failed a few years back and I've just installed an SSD in it .. (finally) .. turns out taking the screen off etc isn't as scary as some people make out 
How old is the MacBook's disk?
(if you say "original" worn out HDD would be my top bet)
I suppose it's possible there's a fault on the Mac's USB port, but somehow it seems unlikely. If it's talking about corrupted files, is it possible it's referring to the hard drive? The reason I have a Mac on my desk is because the disk failed a few years back and I've just installed an SSD in it .. (finally) .. turns out taking the screen off etc isn't as scary as some people make out 
How old is the MacBook's disk?
(if you say "original" worn out HDD would be my top bet)

How old is the MacBook's disk?
(if you say "original" worn out HDD would be my top bet)