The VarFormat function may be unsuccessful when it is used with a format string that contains a period character (.) in x64-based Windows Vista or Windows Server 2008 systems

On a computer that has an x64-based Windows Vista or Windows Server 2008 system installed, when you call the VarFormat function by using a format string that contains a period character (.), and this "." character does not represent a decimal separator, the VarFormat function may be unsuccessful. Instead, the VarFormat function returns an "E_INVALIDARG" value, which means "One or more of the arguments is invalid."

Note The VarFormat function formats a variant into a string form by parsing a format string. See the "More information" section for more information.

Functions that depend on the VarFormat function may also experience the failure in this same scenario. For example, the following user-defined function uses a "." character in a VBA Format function, and this format eventually calls the VarFormat function. You also receive an "Invalid procedure call or argument" Microsoft Visual Basic Run-time error message when you run the following user-defined function in Microsoft Office Excel:

The issue occurs because of a problem with the VarFormat function "foo" that is actually used in this function in the Oleaut32.dll file in x64-based systems.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the �Hotfix Request� page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.

Prerequisites

You must apply this hotfix on x64-based Windows Vista or Windows Server 2008 systems.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista and Windows Server 2008 file information notes

• Service Pack 1 is integrated into Windows Server 2008. Therefore, RTM milestone files apply only to Windows Vista. RTM milestone files have a 6.0.0000.xxxxxx version number.

For all supported x64-based versions of Windows Server 2008 and Windows Vista

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about VarFormat, visit the following Microsoft Web site:For more information about Format function, visit the following Microsoft Web sites: