| Mitigation - |
| Clean boot into Windows, and then attempt the upgrade to Windows 10. + |
| -For more information, see [How to perform a clean boot in Windows](https://support.microsoft.com/kb/929135). +Mitigation + |
| Clean boot into Windows, and then attempt the upgrade to Windows 10.
+
+For more information, see [How to perform a clean boot in Windows](https://support.microsoft.com/kb/929135).
+
+Ensure that you select the option to "Download and install updates (recommended)."
+
+Computers that run Citrix VDA
+You may see this message after you upgrade a computer from Windows 10, version 1511 to Windows 10, version 1607. After the second system restart, the system generates this error and then rolls back to the previous version. This problem has also been observed in upgrades to Windows 8.1 and Windows 8.
+
+This problem occurs because the computer has Citrix Virtual Delivery Agent (VDA) installed. Citrix VDA installs device drivers and a file system filter driver (CtxMcsWbc). This Citrix filter driver prevents the upgrade from writing changes to the disk, so the upgrade cannot complete and the system rolls back.
+
+**Resolution**
+
+To resolve this problem, install [Cumulative update for Windows 10 Version 1607 and Windows Server 2016: November 8, 2016](https://support.microsoft.com/help/3200970/cumulative-update-for-windows-10-version-1607-and-windows-server-2016).
+
+You can work around this problem in two ways
+
+**Workaround 1**
+
+1. Use the VDA setup application (VDAWorkstationSetup_7.11) to uninstall Citrix VDA.
+1. Run the Windows upgrade again.
+1. Reinstall Citrix VDA.
+
+**Workaround 2**
+
+If you cannot uninstall Citrix VDA, follow these steps to work around this problem:
+
+1. In Registry Editor, go to the following subkey:
+ ```
+ HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e967-e325-11ce-bfc1-08002be10318}\CtxMcsWbc
+ ```
+1. Change the value of the **Start** entry from **0** to **4**. This change disables the Citrix MCS cache service.
+1. Go to the following subkey:
+ ```
+ HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e967-e325-11ce-bfc1-08002be10318}
+ ```
+1. Delete the **CtxMcsWbc** entry.
+1. Restart the computer, and then try the upgrade again.
+
+> **Third-party information disclaimer**
+> The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.
- Ensure you select the option to "Download and install updates (recommended)." |