Problem with opening file from external drive

Hi, good day.

I have a problem with opening the cad file from external drive which saved using autodesk or Gstar cad, a dialog box come out saying that only can open as read only. i was using the 64bit draftsight. but it didn't happen on my other pc which is using 32bit draftsight. Now i'm using a notebook running on window 8 - 64 bit.

 

Thank you.