without knowing your software version, the following procedure could help:
Open Offline Data Analysis program, go to File -> New Batch folder and create a new (empty) batch.
Then go to File -> Import All Samples from Batch and select the corrupt batch. The raw data should be imported.
Now you need to re-write the data analysis method from scratch or you import the data analysis method from a different, working batch (DA Method -> Import DA Method).
If this fails, it could be that a single sample is corrupt. Then try importing one or a few samples at the time in your newly created empty batch.
Hope that helps
Thanks you Matthias,
That worked perfectly... data first, then method... all samples present. .. another trick learned!