Log Name: Lync Server
Source: LS Storage Service
Date: 5/16/2017 5:54:02 PM
Event ID: 32071
Task Category: (4006)
Storage Service had a failure while refreshing its calculation of DB space used.
DB Space Used Refresh Error. Object reference not set to an instance of an object.
Cause: The Timer task to refresh the DB space used value ran into an exception. This action will be retried and should auto recover.
Check event details. If problem persists, notify your organization's support team with the event details.
For the moment, not clear what causing it.
Option I consider for the moment are:
install latest Lync CU
install windows patches inside SBA (esp. .NET)
redeploy CS databases
repair SBA image and re-deploy from scratch
some relevant links I collected so far:
update: nothing really helped, we did completely redeploy from usb key.