Customer might notice that the “Pooled with Personal vDisk” type catalogs might be created but these catalogs remain in a “Preparing state”.
When the master image is cloned at the hypervisor, only core settings such as storage, CPU, and networking are duplicated for the newly created machines and all other settings maintain their default values from the hypervisor. Customers that have made changes related to disabling drives, ports, and other hardware loose these changes and the newly created hardware add these devices back and are unable to update the drives as the base image kernel is in a read only state
When configuring the master image, before you take the snapshot that will be used to create your catalog, start the machine into the BIOS of the Virtual Machine and reset all settings to default. This allows you to deploy your new images without them being blocked by newly found hardware. If your security requirements require these devices disabled, then you can remove them from the target devices.
The original article on the Citrix knowledgebase can be found here.