Concordance builder: Concordance builder in PTx8 having issues opening pt7.5 concordance

We’ve got a user who is trying t use the Paratext 8 Concordance builder tool with a concordance that was started in 7.5 When he opens the project in Ptx8 concordance builder, it is in read only mode.

I’m not familiar with how the Concordance builder tool works. Is there something else we can do?