Help opening x_t files?

I have 10 or so x_t files from a supplier.

Half open fine in solid works. 

The other half give an error "Cannot open ***.x_t".

I assume its not a file error as these all open OK in another package.

Any one have any tips, there must be a way to diagnose the file? solidworks gives very little information?

SolidworksImport export