Hi all,
I’ve had this issue and I seem to of got around it with a similar solution used in AVID to rebuild databases. So if you select all of your media that is offline and move it all into a newly created Media/Rushes folder. Then I went to my sequence line and selected all the clips there and right-clicked, Link Media and click down to the new file path to your fresh folder and relink. This worked for me.
Previously trying with the old folder structures I got a message saying it was going to delete the audio or that the files were the wrong media type though the above worked. However saying that you may need to do more than once if you have rushes in various location.