When you try to upgrade an earlier version of a Microsoft Windows operating system to Windows Vista, you receive the following error message:

Windows could not update the computer’s boot configuration. Installation cannot proceed.

If you examine the contents of the drive:$WINDOWS.~BTSourcesPanthersetupact.log file that Windows Vista creates, you notice the following information:

<date> <time>, Info       [0x060216] IBS    CallBack_MungeBootIni:Failed to modify boot entries GLE = 50

In this log entry, GLE error code 50 corresponds to the following error message:

ERROR_NOT_SUPPORTED

Note: Generally, drive is drive C on the computer. However, Windows Vista creates the temporary installation folder depending on many factors. Therefore, this drive may be any supported drive that Windows Vista detects.

For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB931697.

Microsoft has a way to automatically fix this problem, click the "Fix It" image to go to the Knowledge Base page that contains the download.