Error – Another version of this product is already installed

Today, I got an weird error message when trying to remove/install Adobe Pro XI on a user’s machine. It said that another version of this product is already installed.


Here’s the symptom.

  • The app is installed but no icon is shown up in Start Menu
  • No icon in Add/Remove Program
  • The GUID is under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
  • All the files are laid down correctly in %ProgramFiles(x86)%\Adobe\Acrobat 11

After thinking for a while, I tried to search for the word “Adobe” in registry and found a matched “Adobe” word under HKLM\SOFTWARE\Classes\Installer\Products.

After delete the key, I was able to remove and reinstall the app.