A number of users have experienced problems updating to the newly released iTunes 8.1.1. Generally, when this issue occurs, installation appears to proceed normally but then delivers the error message “The installer encounted errors before iTunes could be configured. Your system has not been modified. To retry these operations at a later time please return to the installer again. Click Finish to exit installer.”
This problem can often be fixed by reinstalling the latest version of QuickTime via the following steps:
- Download the latest edition of QuickTime for Windows (make sure to pick the optionwithout iTunes)
- Choose to save the file to your disk, then double-click the .exe file and install QuickTime
- After QuickTime is successfully installed, download iTunes again, choosing to save the file. Double-click the iTunes installer .exe and proceed with installation.
Other potential fixes for this issue include:
Run a disk check Disk errors, particularly in Windows XP, can prevent proper iTunes installation. See this Microsoft Knowledge Base article for instructions on performing a disk check/repair.
Use Windows Installer Cleanup Use the Windows Installer Cleanup tool to remove any references to Apple-related installation files (QuickTime, iTunes, etc.), then re-try using the aforementioned two-step method to reinstall QuickTime and iTunes.