There will be an event ID: 41450 on the Enterprise Vault server stating the following error:
Error. The transform folder path is invalid [E:\Program Files (x86)\Enterprise Vault\EVArchivingReportTransforms]
Cause
The folder named 'EVArchivingReportTransforms' in the installation directory is either missing or corrupt.
You can enable DTrace on the 'EVArchivingReportGenerator' process and can see the below error:
{ReportGenerator.CarryOutAllXSLTransforms} transforms folder does not exist [C:\Program Files (x86)\Enterprise Vault\EVArchivingReportTransforms]
{ArchivingReportGenerator.Main} caught exception [Error. The transforms folder path is invalid [C:\Program Files (x86)\Enterprise Vault\EVArchivingReportTransforms]]
|Event ID: 41450 Cannot generate any archiving reports for 'EX2013-MBX'.|Error. The transforms folder path is invalid [C:\Program Files (x86)\Enterprise Vault\EVArchivingReportTransforms]
Copy the EVArchivingReportTransforms from a working node/ server or you may re-install the EV binaries.