As well-polished an experience Windows is, just like everything tech, it runs into problems now and then. The “Error 1603: A fatal error occurred during installation” is a warning displayed by the Windows Installer Engine and indicates a problem during the installation of a particular program.
In this article, we’re going over error 1603, its causes, and what you can do to fix the problem.
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What causes MSI error 1603?
There are actually a number of reasons why you might encounter this error as listed below.
- Your machine doesn’t have short file name creation enabled.
- A custom action in an install script isn’t defined correctly.
- You’re trying to overwrite a locked file.
- Windows Installer Service isn’t installed correctly.
- Windows temporary folders are full.
- If the setup file got corrupted after installation, you might see this error during uninstallation.
- Install Shield Developer version is outdated.
- Printer and File sharing is not enabled or installed if the application in question needs the service.
- The program you’re trying to install is already installed.
- The folder for the installation path is encrypted.
- The drive for the installation path is accessed as a substitute drive.
- The System drive doesn’t have complete control permissions on the folder you’re trying to install the Windows Installer package.
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6 ways to fix MSI error 1603
Here are six solutions you can use to fix error 1603 on your computer.
Check if the program is already installed
The first thing you should do is check if you’ve already installed the app or program you’re trying to install on your PC.
Step 1: Press Windows key + X to launch the Quick Access menu and select Apps and features

Step 2: Check to see if the program you’re trying to install is already on the list. If it is, uninstall it and try again.

Check if the folder you’re trying to install to isn’t encrypted
Aforementioned, if the destination folder is encrypted, you won’t be able to install any packages there. Check to see if the destination folder is encrypted and if it is, try installing to a different path.
Also read: How to fix Windows 10 install error 0x80300001?
Install the package to a drive that’s not labelled as a substitute
Another rather popular reason why you might be seeing this error is that you’re trying to install the package to a drive that’s being labelled as a substitute in the OS.
To get around it, try changing the installation location, and the error 1603 should go away.
Clear all the temp folders
Emptying all your temporary folders can help free up cache space that installers need to extract and install their packages.

Simply type %TEMP% in the Run prompt, which you can open by using Windows Key + R shortcut and delete all the files from the folder.
Make sure no concurrent apps are running
When installing a package, it’s good practice to close any actively running applications on your PC as they can conflict with the Installer’s requirements.
If you’re running an application in the background while installing something, close the application and try again.
Grant Full Control permissions to the SYSTEM account
If the SYSTEM account on your OS doesn’t have full control permissions, you’re likely to run into errors like these. Follow these steps to resolve error 1603.
Step 1: Open Windows Explorer and right-click the drive you want to install the package to, and click on Properties.

Step 2: Head over to the Security tab and select the SYSTEM account. Make sure it’s got the Full Control permissions enabled. If not, click Edit and add the required permission.

Step 3: Now click Advanced.

Step 4: Select Change Permissions.

Step 5: Select SYSTEM and click on Edit.

Step 6: Select This folder, subfolder and files under the Applies to dropdown and click OK.

Wait for your system to apply the changes and try rerunning the installer package. This should fix “MSI error 1603: A fatal error occurred during installation” on your PC.
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