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When you run the RegClean utility after you install one of the products listed in the "Applies to" section, you may experience one of the following symptoms:

  • The RegClean utility finds errors in the System Registry, and you receive the option to Fix Errors in the RegClean utility.

  • When you install a Microsoft Office program whose installation state is Installed on First Use and then double-click a document that is associated with that program, the Office program may not start. Instead, the Open With dialog box appears and the Office program is not listed.


This issue occurs because the RegClean utility is not compatible with the products listed in the "Applies to" section. This issue occurs for any Microsoft Windows Installer product on which the program's installation state is set to Installed on First Use.


To resolve this issue, try the following methods in the order that they appear in.

Method 1: Undo the Registry Changes from RegClean

To undo changes made by the RegClean utility, locate the Undo.reg file, and then double-click the Undo.reg file. This restores the registry entries that were removed.

The RegClean utility creates a file in the following format:

Undo computeryyyymmddhhmmss.reg
In this example, computer is the computer name, yyyymmdd is the date that the RegClean utility made the registry changes, and hhmmss is the time that the RegClean utility made the registry changes.

Method 2: Demand Install the Office Program

If this issue occurs when you double-click a document from Microsoft Windows Explorer and the document should be associated with an Office program whose installation state is Installed on First Use, follow these steps:

  1. Click Start, and then click Programs.

  2. On the Programs menu, click the shortcut for the Office program that you want to start--for example, click Microsoft Word.

The Office program is installed, and then you can double-click the associated document from Windows Explorer.

Method 3: Remove and Reinstall Office

You may have to remove and reinstall Office to resolve the issue. To do this, follow these steps:

  1. In Control Panel, double-click Add/Remove Programs.

  2. In the Add/Remove Programs Properties dialog box, click the Office entry--for example, click Microsoft Office XP Professional.

    If your operating system is Microsoft Windows 2000 or Microsoft Windows XP, click Remove.

    If your operating system is Microsoft Windows 98, Microsoft Windows NT 4.0, or Microsoft Windows Millennium Edition (Me), follow these steps:

    1. Click Add/Remove

    2. In the Maintenance Mode Options dialog box, click Uninstall Office.

    3. Click Next.

  3. Click Yes to confirm the removal.

  4. When Office is removed, insert your Office CD-ROM, and then run the Setup program to reinstall Office.

More Information

The RegClean utility is no longer supported and has been removed from all Microsoft download sites.

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