After upgrading from a previous version of Neo4j Ops Manager (NOM), the status panel and NOM server logs will display an ApolloError due to null values for the fields pathDelimiter and name, for example:

ApolloError: The field at path '/dbmsById/instances[1]/databaseInstances[12]/storage[0]/pathDelimiter' was declared as a non null type, 
but the code involved in retrieving data has wrongly returned a null value. The graphql specification requires that the parent field be set 
to null, or if that is non nullable that it bubble up null to its parent and so on. The non-nullable type is 'String' within parent type 
'Storage'

The field at path '/dbmsById/instances[1]/databaseInstances[12]/storage[1]/name' was declared 
as a non null type, but the code involved in retrieving data has wrongly returned a null value.
The graphql specification requires that the parent field be set to null, or if that is 
non nullable that it bubble up null to its parent and so on. The non-nullable type is 'String' 
within parent type 'Storage'

Solution

To fix this issue, the following query can be run on the NOM persistence database.

MATCH (n:DatabaseInstance) SET n.storage='[]';

A fix for this issue has also been included in NOM versions 1.8.0 and higher. The latest NOM versions and Release Notes can be found at 
https://neo4j.com/release-notes/nom/ .