The reason for seeing ''Non-operational'' host is because of one of the following reasons:

1. A load test got stuck or crashed.
2. If there is any maintenance taking place and to check the time slots

3. One or more of the 4 services running on the Performance Center host (Load Generator machine) is down.

Please try this suggestion:

1. Please change the status of the host to ''operational'' on the Lab Management page.

2. Go to the Performance Center host (ie. Load Generator machine) and restart all the 4 services.

Please check these Performance Center Services on Hosts are running -

DataCollectionAgent
RemoteManagement Agent Service
Performance Center Agent Service
Performance Center Load Testing Service

3. If the above suggestions do not help, then delete the problematic host and add it back.