Folders on the Veeam Server:
C:\Program Files\Common Files\Veeam
C:\Program Files(x86)\Common Files\Veeam
C:\Users\<Veeam ONE service account name>\AppData\Local\Veeam
Due to the complex nature of antivirus software some additional exclusions may be needed.
If your antivirus has logging or history, please, check the information presented there to confirm whether the antivirus is affecting Veeam ONE operations.