NPrinting error: Illegal operation attempted on a registry key that has been marked for deletion

The error message  appears in the log files. NPrinting cannot access the QlikView application so the report is not generated.

The problem is a QlikView registry key that must be replaced. This may occur after an upgrade.
Restarting the machine and opening QlikView as an administrator forces the correct replacement of the registry key.

The other cause may be the QlikView Desktop client having become corrupted.  Uninstalling and reinstalling the QlikView Desktop client should resolve the issue.

Reference: https://blogs.msdn.microsoft.com/distributedservices/2009/11/06/a-com-application-may-stop-working-on-windows-server-2008-when-the-identity-user-logs-off/

The policy setting 'Do not forcefully unload the user registry at user logoff' counters the default behavior of Windows 2008 R2 and following servers. When enabled, Windows Server does not forcefully unload the registry and waits until no other processes are using the user registry before it unloads it.

• Open the computer policy editor (gpedit.msc). The necessary policy can be found in the group policy editor
• Open: Computer Configuration->Administrative Templates->System-> UserProfiles 
• Change Policy: Do not forcefully unload the user registry at user logoff
• Change the setting from “Not Configured” to “Enabled”, which disables the new User Profile Service feature. ('DisableForceUnload' is the value added to the registry)
• Restart the NPrinting server service (or services if NP 17)

If you are unable to modify the policy in the near term and if you still receive this error message in the future, do the following:
1. Stop the NPrinting Service and Reboot the machine
2. Open QlikView Desktop client as administrator
To do this, go to the QlikView installation folder (C:\Program Files\QlikView)
Right click on the Qv.exe file and choose "Run as administrator"
3. Restart the NPrinting service
4. Remove/Uninstall
5. Re-install the QlikView Desktop client
6. Reboot