Fix error 1721 in Windows 7, Vista and XP
Error 1721 can occur when you try to uninstall a program using the “Add/Remove Programs” or “Uninstall a Program” dialog box. This error occurs due to internal corruption in the operating system files. Running a registry cleaning scan to repair damaged areas of the operating system is usually the correct way to fix Windows error 1721 on Windows 7, Vista, and XP.
The error is basically the result of a problem with the Windows Installer package. Windows Installer is a tool used to install, uninstall, and repair most programs on your computer. Let’s discuss some things that helped many people who faced a similar problem.
Re-register the Windows installer
To remove the programs on your computer, Windows Installer must be in good working order. If your installation is corrupted, you may receive error 1721 in Windows 7, Vista, and XP during the removal process of the program. Simply re-registering your component files would solve your problem.
Restart your computer.
Press the F8 key and select the “Safe Mode with Networking” option.
Press ENTER.
Click Start | All programs | Accessories.
Right click on “Command Prompt” and select “Run as administrator”.
Type the following commands one by one while pressing ENTER after each command separately:
msiexec /unregister
msiexec /log server
exit
Windows Installer Repair
The best way to fix Windows error 1721 is to remove unwanted registry entries and repair corrupted information stored in the Windows Installer registry paths.
First of all, you need to download a good Registry Cleaner software. It will then start a full registry scan and fix any problems found within the Windows Installer registry paths. After scanning the Windows registry through the registry repair software, it will simply reboot your system.
Run System File Checker
System File Checker (SFC) can help resolve error 1721 as by its nature it scans system files for damage and replaces them with their original versions. This requires that you have the Windows installation DVD ROM to proceed.
Insert the Windows installation disc you have.
Click Start | Run.
Type “SFC /ScanNow” and press ENTER.
Restore the system
By restoring your system state to an earlier date, error 1721 may not appear on Windows 7, Vista, and XP. There is a tool called System Restore that we need to use in this procedure.
Click Start | All programs | Accessories | System Tools | System restore.
Click Next.
Select a restore point where the 1721 error did not appear.
Click “Restore my computer” and follow the simple instructions on your screen.
Disable the real-time protection of your antivirus protection
Real-time protection refers to a feature of your antivirus that continuously scans files processed by active programs. Your antivirus’s real-time protection may be conflicting with Windows Installer and thus causing error code 1721 on your Windows 7, Vista, or XP.
The following are the general steps required to disable the real-time protection of your antivirus. However, the steps may vary by product.
Right-click on your antivirus software and select “Real-time protection”.
Click the “Disable” option.
Disable User Account Control (UAC)
UAC stands for User Account Control. Conflicts between UAC and Windows Installer result in error 1721. Disable UAC with the steps shown here:
Click Start and then Control Panel.
In Control Panel, click User Accounts.
In the User Accounts window, click User Accounts.
In the User Accounts task window, click Turn User Account Control on or off.
If UAC is currently set to Admin Approval Mode, the User Account Control message appears. Click Continue.
Clear the Use User Account Control (UAC) to help protect your computer check box, and then click OK.
In Windows 7 change the UAC levels through the settings option.
Click Restart Now to apply the change immediately, or click Restart Later and close the User Accounts task window.