Symptoms
A system upgrade from Windows 10 Version 1511 to Windows 10 Version 1607 fails and generates the following error message: 
This error occurs after the second system restart. After this error occurs, the system rolls back to the previous version.
0xC1900101 - 0x40017

This error occurs after the second system restart. After this error occurs, the system rolls back to the previous version.
Cause
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. This triggers the system rollback.
Resolution
To resolve this problem, follow these steps:
- Uninstall Citrix VDA (VDAWorkstationSetup_7.11).
- Run the Windows upgrade again.
- Reinstall Citrix VDA.
Workaround
To work around this problem, follow these steps:
- Disable the Citrix MCS cache service in the registry by changing the start value from 0 to 4, as shown in the following screen shot.
- Delete the CtxMcsWbc entry in the following subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e967-e325-11ce-bfc1-08002be10318}
- Restart the computer, and then try the upgrade again.