If you wish to do a clean NPrinting install where you have had over versions of NPrinting previously installed, then do the following to clean up the previous install of NPrinting 17.x.x platform. 

(Note: If you had NP 16.x.x  or older platform installed previously as well, simply un-install the software, then open an administrative command prompt and run the syntax found between the following comments "sc delete NPrintingService")

PLEASE NOTE follow the steps in the correct order below or the cleanup/uninstall process will not work normally.

• Open task manager and do 'End task' on epmd.exe
• Uninstall NPrinting Engine, Server and Designer as needed
• Uninstall all versions of Erlang OTP  
• If you had a very old version of NPrinting previously (17.2.x or lower), make sure to also un-install any Rabbit MQ remaining in Programs and Features/uninstall a program

Next, open the following and rename these folders:

• C:\Program Files\NPrintingServer to C:\Program Files\NPrintingServer.old
• C:\ProgramData\NPrinting to C:\ProgramData\NPrinting.old
• Restart the server

NOTE: if you not able to rename the folders, restart the server and try to re-name again.

Once you are able to rename the folders, Install NPrinting server once again but make sure that you have met all system and user account requirements before proceeding.

For example

• you must have a least 2 cores on your computer (see install requirements)
• The NP service account must have log on as a service right before proceeding (see install requirements
• etc

If this does not solve the issue, please start a support case so we can assist you further to clean up your machine in further detail before attempting another re-installation.