Lot's of Google results about editing import specification. You could try them or the easiest might be to recreate the import. Here's just one.
https://social.msdn.microsoft.com/Fo...orum=accessdev
If this happened because file(s) got moved there's not much you can do to prevent it. If the problem is because a user has the exact same folder mapping but their drive letter is different, then it's better to use UNC paths where possible, instead of drive volume labels (e.g. D, E, F and so on).
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.