Is there any way to prevent Storage Spaces Direct from automatically adding disks?

Yes, you can disable the auto-pooling behavior. The experience is not great, but it’s certainly do-able and supported. The setting name, and example cmdlet syntax, is in the Settings section of this public doc:

https://technet.microsoft.com/en-us/windows-server-docs/failover-clustering/health-service-overview

Essentially, run this as Administrator:

Get-StorageSubSystem Cluster* | Set-StorageHealthSetting -Name "System.Storage.PhysicalDisk.AutoPool.Enabled" -Value False

Hope this helps! - Cosmos (@cosmosdarwin), Microsoft PM

The workaround i've found to this problem is to change the Bus Type of the RAID volumes or disks by changing it from one of the supported type to an unsupported one.

You will have to identify the controller driver from Device Manager and after go on registry and find the driver name on the location below.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SmartPqi\Parameters

In my case, i've changed the registry key that correspond to SAS into RAID

«BusType»=0x00000008 (RAID) (instead of 0x0000000a) (SAS)

reboot the machine

After this change you can have the storage pool in Windows Storage subsystem instead of Clustered Storage Spaces

Please be careful if you want to apply this type of workaround as it's not a validated solution and might expose your production environment to a high risk.