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Home » How to Fix Windows Installer Error 1721 – A Detailed Guide

How to Fix Windows Installer Error 1721 – A Detailed Guide

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Windows Installer Error 1721 is a common windows error that raises when windows is unable to install msi package due to various reasons. You may get following error message:

“Error 1721: There is a problem with this Windows Installer package. A script required for this install to complete could not be run. Contact your support personnel or package vendor.”

Error 1721 Fixed


There are following main reasons behind this error.

1. Missing System Files like exe file, dll file, sys file, ocx files etc. These are the important system files which is responsible to run your PC hassle free.

2. Windows Installer Problem: Windows Installer File Msiexec.exe is responsible for adding and removing program from your PC.

3. Invalid Registry Entry: Registry Files are the very important system files and once it gets damaged or get invalid entries, it becomes irresponsible and thus system causes so many problems.

How to Fix Windows Installer Error 1721

Method 1: Fix using Advanced System Repair Tool

The most of the common reason behind program install failed is corrupted or damaged system files like DLL files, EXE files, sys files etc. There are thousands of tiny system files are there that work specific task. If one of the files gets replaced, deleted or damaged then you may get windows installer error 1721.

Windows is made with huge number of dll files, exe files, sys files, various types of services, databases, etc so, it is not possible to keep monitoring all the files always. A brilliant PC Optimizer tool repairs damages, fix errors, update windows and drivers, and eliminate various types of errors silently.

Outbyte PC Repair Tool does all the above task easily and provides you an errorfree and smooth Windows environment to work so that you can focus on your business only.

3 Steps to Fix this Error
Step 1. Download Outbyte PC Repair Tool [File Size: 16.4 MB]
Step 2. SCAN your Windows PC
Step 3. Click Fix button to Repair Error

Download and Install Advanced System Repair Tool and scan your PC. It has the large database with 25 million of files. It will find all the damaged or deleted system files and reinstall them with the fresh one. After, optimizing with Advanced System Repair Tool, try to install software again.

Method 2: Re-register the Windows Installer File.

As I discussed above that Msiexec.exe is a Windows Installer File that is responsible for adding and removing software from PC. If this file becomes inaccessible then system is unable to install and uninstall any software. In order to fix this problem, you need to Re-register this file.

Step 1: Open Run Dialog Box by pressing Windows Key + R simultaneously.
Step 2: Type MSIEXEC /UNREGISTER in Run Dialog box and click OK. This command will display nothing but unregister the Msiexec.exe file.

Step 3: Open Run Dialog box again and Run the following command to register Msiexec.exe file again.


Now, restart the computer and examine the error 1721, whether it appears again or not. Before restarting PC you must bookmark this article because if this method doesn’t work then here is detailed guide to fix this error.

Method 3:

Disable Antivirus software and Firewall then try to install software. Apply this method only when you fully trust the application.

Method 4:

Run sfc /scannow command to repair system file. If there would be any problem in windows files, this command will repair them automatically. Open Command Prompt as administrator and paste following command and hit Enter.

sfc /scannow

This command will search for entire system files and replace damaged/incorrected system files with correct microsoft files.


In this chapter, I’ve tried to explain 4 ways to fix Windows Installation Error 1721. If you are getting trouble in removing installation error 1721, then why don’t you use Advanced System Repair Tool. This is not a tool, this is a weapon against windows problems. Must try!

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