The vendor has published 2 unique mention(s) for this bug: 1. Machine Creation Services I/O (MCSIO) 2. When using Machine Creation Services I/O (MCSIO) with Windows Server 2019 VDAs running VDA 2607 , the write-cache disk is successfully attached to the provisioned virtual machine but remains empty and is not utilized as expected. This issue has been observed only under the following conditions: The VDA operating system is Windows Server 2019 VDA 2607 is installed The machine catalog is provisioned using MCSIO Workaround Configure the required CVhdFilter registry setting on the master image before provisioning machines. Registry location: HKLM\SYSTEM\CurrentControlSet\Services\CVhdFilter Resolution Steps On the Windows Server 2019 master image, open Registry Editor (regedit.exe) . Navigate to: HKLM\SYSTEM\CurrentControlSet\Services\CVhdFilter Right click on CVhdFilter and create a new empty key 'Parameters'. Reseal or shut down the master image. Create a new snapshot of the master image. Update the MCSIO machine catalog to use the new snapshot. Reboot the provisioned virtual machines. Verify that the write-back cache (WBC) disk is populated during normal user session activity. Affected Versions Citrix Virtual Delivery Agent (VDA) 2607 Windows Server 2019 Machine Creation Services I/O (MCSIO) Latest urls for this bug: 1. https://docs.citrix.com/us/en/citrix-virtual-apps-desktops/2607-ltsr/whats-new-node/known-issues.html