NSIS Error and Cannot or Unable to Open and Install Setup Installer

After downloading some software programs’ setup installer from Internet, such as BitTorrent, BitLord, iTunes, McAfee Site Advisor, Ethereal, Winamp and many other applications or drivers, users may face a problem where the setup executable cannot be installed. Whenever attempt to install, the installation will fail with the following error message.

NSIS Error

The installer you are trying to use is corrupted or incomplete.
This could be the result of a damaged disk, a failed download or a virus.

You may want to contact the author of this installer to obtain a new copy.

It may be possible to skip this check using the /NCRC command line switch
(NOT RECOMMENDED).

Or,

NSIS Error

Installer integrity check has failed. Common causes include
incomplete download and damaged media. Contact the
installer’s author to obtain a new copy.

More information at:
http://nsis.sf.net/NSIS_Error

The NSIS (Nullsoft Scriptable Install System) error message box basically means that the setup executable or installer user is trying to run is corrupted, or incomplete. However, often it’s not the actual cause.

If you’re unsure of whether you have downloaded a complete and correct version of installer file, try the few solutions posted on NSIS open source page to ensure that the setup installer is valid and not corrupted.

If you are confident and verify that the installer is indeed valid and in good condition, but still encounter the NSIS Error dialog box and stop halt and fail the installation, then another possible reason for NSIS error to appear is problematic network connectivity, either due to faulty network card, or Internet or LAN connection to upload, download and transfer files been blocked or restricted.

Network adapter failure is unlikely to be a common cause, unless you have problem surfing or downloading the file too. So, the resolution to NSIS Error can come down to simply checking if there is any firewall or other security software running on the computer that causing the NSIS Error.

One possible candidate is Windows Firewall which exists in Windows XP and later operating system such as Windows 2003, 2008 and Windows Vista. The solution is to disable the Windows Firewall and run the installer again.

Other reported problem maker that trigger NSIS Error include integrated nVidia NIC (network interface card) that includes a firewall. In this case, user have to change the network adapter to one without firewall or switch to wireless network temporarily to get the installer installed, as disabling the network card will still cause NSIS Error.