WINDOWS INSTALLER ERROR · ERROR_INSTALL_FAILURE
Error 1603: Fatal Error During Installation
Error 1603 is the generic way Windows Installer says an installation or removal failed. The number does not name the cause. Microsoft documents four conditions that produce it when a package is installed, and says that after you click OK the installation rolls back.
WHAT WINDOWS SAYS
A fatal error occurred during installation.
Microsoft's troubleshooting article shows it as "Error 1603: A fatal error occurred during installation." Windows Update and some setup programs show the same number as 0x80070643: Microsoft's error list gives 1603 as 0x643, and 0x80070643 is that code written as an HRESULT.
Wording from Microsoft's documentation, linked under Sources.
TECHNICAL SUMMARY
| Number | 1603, 0x80070643 |
|---|---|
| Windows name | ERROR_INSTALL_FAILURE |
| Where it appears | Exit code of msiexec.exe |
| In PC Tweaker Uninstaller | Shows the exit code |
What causes Error 1603
- Windows Installer is trying to install an app that is already installed on the PC. Microsoft adds that a desktop shortcut can be lost in a Windows upgrade while the app itself stays installed.
- The folder you are installing to is encrypted.
- The drive that contains that folder is accessed as a substitute drive.
- The SYSTEM account does not have Full Control on that folder. Microsoft explains that the Windows Installer service uses the SYSTEM account to install software.
- For .NET Framework updates, Microsoft calls 0x643 and 1603 generic codes that typically mean the update was not installed, usually because of a corrupted .NET Framework installation or an inconsistent Windows Installer database.
How to fix Error 1603, safest step first
Microsoft gives one resolution per cause, in this order. The restore point is ours and comes first; each step says how to put back what it changed.
Make a restore point before the steps that change something
Select Start, type Create a restore point, open it, and on the System Protection tab choose Create. Microsoft notes that System Protection is not turned on by default; if Create is greyed out, choose Configure and turn it on for the system drive first.
To undo: A restore point changes nothing by itself. To go back later, run System Restore and pick it: Microsoft says it reverts system files, the registry and installed programs, and leaves your personal files alone.
Check whether the app is already installed, then uninstall and reinstall it
Select Start > Settings > Apps > Installed apps and look for the app. If it is listed, uninstall it there, restart, and run the setup again. If only the shortcut was lost, Microsoft's alternative is to search for the app and pin it to Start instead.
To undo: Uninstalling is undone by installing the program again. Whether your settings survive depends on the program.
Install to a folder that is not encrypted
If the target folder is encrypted, choose another folder in the setup, or clear the encryption on that folder first (right-click it > Properties > Advanced > Encrypt contents to secure data).
To undo: Tick the same Encrypt box again after the installation if you cleared it.
Install to a drive that is not a substitute drive
A substitute drive is a drive letter created with the subst command that points at a folder. Install to the real path, such as a folder on C:, instead of the substituted letter.
To undo: Nothing to undo: only the destination of the installation changes.
Give the SYSTEM account Full Control on the target folder
In File Explorer, right-click the drive or folder you are installing to > Properties > Security. If SYSTEM is not listed, choose Edit > Add, type SYSTEM, select Check names and OK. Select SYSTEM and allow Full Control, then in Advanced make the entry apply to this folder, subfolders and files. Microsoft's article lists these steps one by one.
To undo: Write down the SYSTEM entry's permissions before you change them, and set them back on the same Security tab.
Repeat it once with a log, to see the step that failed
From an administrator Command Prompt run
msiexec.exe /i "C:\path\setup.msi" /L*V "%TEMP%\msi-install.log". Microsoft documents /L*V as logging all information including verbose output. Open the log and read the lines just before the error number.To undo: This runs the real setup or removal again, so it is not a dry run. The log is a text file you can delete.
Check it yourself, without changing anything
Read what Windows Installer logged (PowerShell)
Microsoft documents event 1033 (installation completed with status) and 1034 (removal completed with status): each names the product, its version and the status number, which is 0 on success. Nothing is changed.
PowerShellGet-WinEvent -FilterHashtable @{ LogName='Application'; ProviderName='MsiInstaller'; Id=1033,1034 } -MaxEvents 10 | Format-List TimeCreated, Id, MessageList substitute drives (Command Prompt)
With no arguments, subst only lists the virtual drives that exist. No output means there are none. Nothing is changed.
cmdsubst
What PC Tweaker Uninstaller does with Error 1603
Shows the exit codePC Tweaker Uninstaller removes a Windows Installer program with the command it shows you first in the Removal Brief, msiexec.exe /x {ProductCode} /qn /norestart, after asking Windows for a restore point when the removal needs administrator rights. If msiexec.exe returns 1603, the report reads "The uninstaller exited with code 1603. The program may not be fully removed — refresh the list to check." and the failed attempt is kept in the Removal Ledger with that code. The Uninstaller does not retry, change folder permissions or repair Windows Installer, and it has no part in Windows Update, where the same number appears as 0x80070643.
PC Tweaker Uninstaller: see the exact command before a removal runs
Common questions
Is 0x80070643 the same error as 1603?
Yes, it is the same Windows error in another notation. Microsoft's system error list gives ERROR_INSTALL_FAILURE as 1603 (0x643), and 0x80070643 is that code written as an HRESULT. Windows Update shows it for an update that did not install; Microsoft calls 0x643 and 1603 generic codes that typically mean the update was not installed.
Why do I get error 1603 for a program that is already installed?
It is the first cause Microsoft lists: Windows Installer is trying to install an app that is already on the PC. Microsoft notes the app can still be installed after its desktop shortcut was lost in a Windows upgrade. Uninstall it from Settings, then run the setup again.
Does error 1603 mean Windows is damaged?
Not by itself. Microsoft describes 1603 as the message for a failed installation that rolls back, and lists causes in the app or the target folder: already installed, an encrypted folder, a substitute drive, or missing SYSTEM permissions.
Where do I find the real cause behind a 1603?
In the log. Windows Installer writes event 1033 for an installation and 1034 for a removal to the Application log, with the product and the status number. A verbose log made with /L*V shows the step that failed in the lines before the error.