If more than 100 jobs are running simultaneously, and the user attempts to start more jobs, they may fail to start with the following error message:
Error Job <JobName> cannot be started. SessionId: <UUID>, Timeout: [361 sec]
This issue is due to many session running which causes the Veeam services to be impacted by the Desktop Heap limitation. This is because the Desktop Heap size for services is much smaller than that for applications.
To resolve this issue the Desktop Heap size must be increased via a registry modification.
Because this change will affect the desktop heap of all services (also known as non-interactive window stations), do not make the new value larger than necessary.