How to Fix a Corrupted Windows Installer

Installing new software and components onto your computer is a risky activity. Over the years, Microsoft has taken many steps to protect your system from becoming corrupted by a bad installation, but it can still happen. Sometimes, a bad installation can even corrupt the Windows Installer itself, causing subsequent installations that rely on the Windows Installer to fail. This can trap your system in a loop, where you can't fix the installer without installing new software, which won't install because the installer is broken.

Checking my email
credit: m-imagephotography/iStock/Getty Images

Fixing Corrupted Registry Keys with the Microsoft Fix It Solution Center

In some cases, what seems like a problem with the Windows Installer may actually be a problem with corrupted registry keys, and for some of these problems Microsoft has an automatic fix. Visit the Microsoft Fix It Solution Center on the Web. There, on Step 3, where it says "Filter Solutions," type "Fix problems that programs cannot be installed or uninstalled" without the quotation marks, and then click "Run Now" on the solution that comes up, or click "Learn More" to get a better idea of what the solution will do. After you run the fix, restart your computer and try the installation again.

Fixing Windows Update with the Microsoft Fix It Solution Center

(This section Ref. 2) If you're having a problem with Windows Update in particular, navigate to the Microsoft Fix It Solution Center and in the Step 3 search box filter type "Fix the problem with Microsoft Windows Update that is not working" without quotation marks, then click "Learn More" and follow Microsoft's instructions for troubleshooting the problem.

Unregistering and Re-Registering the Windows Installer

(This section Ref. 3; see note in Writer Comments) Swipe in or click the Windows Start Button and in the Search field type "Services." Then click on the "Services" application that shows up in the results. Scroll down the list of services and double-click "Windows Installer." The Windows Installer Properties window will open, and, under the Service Status section, if the service is currently listed as "stopped" then click the "Start" button. Click "OK" to close the window. Next, unregister and re-register Windows Installer -- this is a way of cleaning up corrupt information. Go back to the Start Button and in the Search field type "MSIEXEC /UNREGISTER" without quotation marks, then press "Enter" or click "OK." Go back to the Search field and this time type "MSIEXEC /REGSERVER" without quotation marks, and press "Enter" or click "OK." Restart your computer and try the installation again.

Cleaning the System Registry

(This Section Ref. 4) If you're still having problems with Windows Installer, you can clean out some of the data in your system registry that may be corrupting the installer. Be warned that modifying registry settings incorrectly can make your computer unusuable. Before attempting this fix, back up your files and create a system restore point. When you're ready, swipe in or click the "Start" button and type "Regedit" in the Search field. Click on the "Regedit" program when it appears in the results. Click "Yes" if Windows asks your permission for the Registry Editor to make changes to your computer. Navigate through the registry directory to this location:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Installer\

Right-click on the "Installer" folder and select "Permissions." Click "SYSTEM" and make sure that SYSTEM has the permission check box marked "Full Control."

Then navigate here:

HKEY_LOCAL_MACHINE\Software\Microsoft\Updates\

Click on the "Updates" folder. Double-click on the "UpdateExeVolatile" key on the right side of the window, and enter the value data as "0" without quotation marks. Then click "OK." Restart your computer and try the installation again.

If that doesn't work, or if the Updates folder or UpdateExeVolatile key don't exist, then don't worry. The UpdateExeVolatile key has to do with software installations, and if it gets messed up it can cause a problem with Windows Installer. However, it's just one possibility, so if this isn't the answer then move on to the next step by navigating here:

HKEY_LOCAL_MACHINE \System\CurrentControlSet\Control\Session Manager\

Right-click the "PendingFileRenameOperations" key on the right side of the window and click "Delete" from the drop-down menu, then confirm your selection when prompted. Restart your computer and try the installation again.

If that doesn't work, or if the key doesn't exist, don't worry. The "PendingFileRenameOperations" key has to do with files that get renamed while in use, and if this data gets messed up it can cause problems with the installer. But, again, it's only one possibility, so if this isn't the answer then move on to the next step by navigating back to the installer folder:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Installer\

Click on the "Installer" folder. Right-click the "InProgress" key on the right side of the window and click "Delete" from the drop-down menu, then confirm your selection when prompted. Note that this key might not exist if your system doesn't have any installations in progress. Restart your computer and try the installation again.

Other Steps

If none of the solutions fix your problem, restore your system to a point before the problem started. If that doesn't work either, you can try reinstalling the Windows Installer. Windows versions 7 and 8 use Windows Installer 5.0, which isn't available as a standalone redistributable download; So, in the case of Windows 8, you'll have to download the Windows 8 Software Development Kit, which will give you access to a fresh copy of Windows Installer 5.0. If that doesn't work, or if you're not able to install the SDK because of the installer problem, you may have to hire a technician to look at your computer.