If you need to run a script to stop a service in order to get...

In the guest processing setting of the job, enable application-aware processing and add a pre-freeze script to the VM

Configure the script to run on the Veeam Backup & Replication server using the Windows Task Scheduler

Copy the script to the VM and schedule the script to run prior to the start of the backup job using the Windows Task Scheduler in the VM

In the virtual machines setting of the job, add a script in the scripts tab under “Run the following script before the job:”