The VBRCatalog is by default located at C:\ on the Veeam Server, and you may need to change the location.
You will need to make changes to the registry to change the VBRCatalog folder location. To do so:
1. Stop the Veeam Services
2. Check the permissions that are set on the folder
3. Unshare the folder and move it to a new location
4. Now share the folder and reset the permissions
5. Then navigate to the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Veeam\Veeam Backup Catalog
Find the string called CatalogPath, right-click it and choose modify
Under Value Data, edit the field to display the new location
6. Restart the services mentioned above
Please be aware that starting from September 2018 downloading updates will require an active contract for the corresponding product.