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10 Tech How-To

Fix Windows Installer Package DLL Error on Uninstall

Guide 10-4889 · Updated · Step by step

This guide walks you through fixing the “Windows Installer Package” DLL error that appears when you try to uninstall a program. The error usually says something like “There is a problem with this Windows Installer package. A DLL required for this install to complete could not be run.” You’ll learn the exact steps to clear the corrupted cache, repair the Windows Installer service, and remove the stubborn program safely.

What You’ll Need

  • An administrator account on the Windows PC
  • The original installer file (.msi or .exe) for the program you’re trying to remove, if you still have it
  • A stable internet connection (for downloading the Microsoft Program Install and Uninstall Troubleshooter if needed)

Step-by-Step

  1. Close all running instances of the program. Check the system tray (bottom-right corner) for icons of the program and right-click to exit. Also open Task Manager (Ctrl+Shift+Esc), look under “Processes” for anything related to the program, select it, and click “End Task.”
  2. Run the uninstaller as administrator. Go to Control Panel > Programs > Programs and Features (or Settings > Apps > Installed apps). Find the program, click it, and select “Uninstall.” If a User Account Control prompt appears, click “Yes.” If the error appears, note the exact wording and click OK to close it, then proceed to the next step.
  3. Clear the Windows Installer cache folder. Press Win+R, type %windir%\Installer, and press Enter. This opens a hidden folder. Do not delete files here manually—instead, right-click an empty area and sort by “Date modified.” Look for files with a .msi or .msp extension that match the program you’re trying to remove, often identifiable by the file name or date. If you find one, right-click it and select “Uninstall” (this is a hidden option). If that fails, move on—do not delete the entire folder contents.
  4. Repair the Windows Installer service. Press Win+R, type services.msc, and press Enter. Scroll to “Windows Installer,” right-click it, and select “Start” if it’s not running. Then right-click again and select “Properties.” Set “Startup type” to “Manual” (this is the default), click “Apply,” then “OK.” If the service won’t start, restart the PC and try again.
  5. Run the Microsoft Program Install and Uninstall Troubleshooter. Download the official tool from Microsoft’s website (search “Microsoft Program Install and Uninstall Troubleshooter”). Run it, accept the license terms, and select “Uninstalling.” Choose the problematic program from the list and follow the prompts. This tool automatically fixes corrupted registry entries and installer cache problems.
  6. Use the original installer file to uninstall. If you have the original .msi or .exe setup file, right-click it and select “Run as administrator.” The setup wizard should give you a “Repair” or “Remove” option. Choose “Remove” and follow the steps. If the wizard only offers “Repair,” run that first, then try uninstalling again from Control Panel.
  7. Remove leftover registry entries (advanced, backup first). Press Win+R, type regedit, and press Enter. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall and also HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall (for 32-bit programs on 64-bit Windows). Look for a key with the program’s name. Right-click the key and select “Export” to back it up, then right-click and delete it. Close the registry editor and restart the PC. The program should no longer appear in the installed programs list.
  8. Use a third-party uninstaller as a last resort. Tools like Revo Uninstaller (free version) or Geek Uninstaller can force-remove a program and clean its leftover files and registry entries. Download one, run it, find the program, right-click and select “Force Uninstall” or “Uninstall.” Follow the prompts to scan for leftovers and delete them.

Common Mistakes

  • Deleting the entire C:\Windows\Installer folder. This folder contains cached installers for many programs. Deleting all of it can break other software and Windows updates. Only attempt to remove specific .msi files that clearly match the problem program.
  • Skipping the reboot. After repairing the Windows Installer service or clearing registry entries, a restart is often required for the changes to take effect. Trying to uninstall immediately after a fix may still show the error.
  • Running the uninstaller without admin rights. Many MSI packages require elevated privileges. Always right-click the uninstaller or setup file and select “Run as administrator.”
  • Manually deleting the program’s folder. If you delete the installation directory (e.g., C:\Program Files\ProgramName) without uninstalling, the registry still thinks it’s installed, and future attempts to install or uninstall will fail with the same or similar errors.

Tips

  • Check the Windows Installer log. When the error appears, look in the Temp folder (type %temp% in Run) for files like MSI*.log. Open the most recent one with Notepad and search for “Return value 3” or “DLL” to see which specific DLL failed. This can tell you if it’s a missing system file (like a Visual C++ runtime) that you can reinstall separately.
  • Reinstall the program over itself. Sometimes running the original installer and choosing “Repair” fixes the broken DLL registration, after which the uninstall works normally.
  • Create a system restore point. Before making registry edits or using a third-party uninstaller, create a restore point (search “Create a restore point” in Start). This gives you a rollback option if something goes wrong.
  • Use Safe Mode. If the error is caused by a background service or antivirus interfering, boot into Safe Mode (hold Shift while clicking Restart, then Troubleshoot > Advanced Options > Startup Settings > Restart > press 4). Uninstall from Safe Mode often bypasses the interference.

Troubleshooting

The error still appears after Step 4. The Windows Installer service may be disabled. Open services.msc again, double-click “Windows Installer,” and check that “Startup type” is not “Disabled.” If it is, set it to “Manual,” click “Start,” then try uninstalling again.

The Program Install and Uninstall Troubleshooter says “no problems found.” The tool doesn’t always detect corrupted MSI patches. Try running the uninstaller from the original setup file (Step 6) or use the registry cleanup method (Step 7).

You cannot find the program in the registry. The uninstall key may be under a different name (e.g., a GUID like {1234-5678…}). Search the registry for the program’s name using Edit > Find (Ctrl+F). If you find nothing, the program may have been installed per-user—check HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Uninstall as well.

Third-party uninstaller leaves an entry in Programs and Features. After force uninstalling, the registry key may remain. Manually delete the corresponding key as described in Step 7, then refresh the list.

The error mentions a specific DLL like “msi.dll” or “msiexec.exe”. This suggests a corrupted Windows Installer system file. Run sfc /scannow in an elevated Command Prompt (Win+X > Command Prompt (Admin)). If it finds and fixes errors, restart and try uninstalling again.

Frequently Asked Questions

Q: Is it safe to delete files in the C:\Windows\Installer folder?
A: No, not in general. That folder stores cached MSI files for many programs. Deleting the wrong file can break updates or uninstalls for other software. Only delete a specific .msi if you are certain it belongs to the program you’re removing, and even then, prefer using the original installer or a dedicated uninstaller tool.

Q: Why does this error happen?
A: It usually occurs when a DLL file required by the Windows Installer package is missing, unregistered, or blocked. Common causes include a failed update, antivirus software locking the file, a partially completed installation, or leftover registry entries from a previous manual deletion.

Q: Can I just reinstall Windows to fix it?
A: That would fix it, but it’s overkill. The steps in this guide resolve the issue in most cases. Only consider a Windows reset or repair install if the program is completely stuck and you’ve exhausted all other options.

Q: Will this fix affect other installed programs?
A: The methods here are targeted at the one problematic program. Clearing the Windows Installer cache folder or editing the registry for that specific program should not affect others. However, using a third-party uninstaller’s “force remove” might delete shared DLLs if you tell it to—always review the leftover files it finds before deleting.

Q: The error appears but the program is already gone from my PC.
A: This happens when the uninstall was partially completed. The registry still references the program. Use Step 7 to remove the registry key, and also check for leftover folders in Program Files and AppData (press Win+R, type %appdata% and %localappdata%) and delete any remaining folders for that program.

Q: Do I need to download anything if I don’t have the original installer?
A: The Microsoft Program Install and Uninstall Troubleshooter (Step 5) is the main external tool. If that fails, a third-party uninstaller is your best bet. Both are free and safe to use from official or reputable sources.

Related

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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