What does this error mean?
This error is a catch-all error for node tool when running either nodetool import or nodetool refresh.
Why does this error occur?
The exact problem would depend on the specific root cause, which should be reported by nodetool. For example it could be due to corrupt sstable files or directory permissions on the default data directory.
How do you fix this error?
Depending on the root cause reported by nodetool, there will be different needs to address. If nodetool is reporting corrupt SSTables files, hardware checks should ensue. If nodetool reports directory permissions, a simple chmod may be the fix. Follow the nodetool message to determine what the cause is and how to fix. If you are unsure how to fix, please open a support ticket with DataStax Support.