The "Cassandra" service will not start successfully, after a new hash set was imported.
If it is determined that Cassandra was running successfully until a recent import of hash data, then it could be that the Cassandra commit logs are corrupted.
To remove commit logs and allow Cassandra to recreate them:
1. Delete the commitlog folder located at: C:\Program Files\AccessData\Cassandra\data\
2. Restart the computer.
See the "apache.org" links below for additional detail.
This webpage describes a commit log corruption issue in cassandra 3.1.1
If commit log repair is set to occur automatically, then see below to allow Cassandra to ignore corruption upon subsequent starts.
Cassandra (which is the KFF service for Accessdata application versions 6.3 and later)
FTK/AD Enterprise/AD Lab version 6.3 and above
Summation Pro/AD Ediscovery version 6.3 and above