FIX: Incorrect results in a project if /Ob2 and the Release mode are used in Visual Studio 2010 SP1


Consider the following scenario:

  • You develop a project in Microsoft Visual Studio 2010 Service Pack 1 (SP1). The project has inline functions.

  • You set the Inline Function Expansion compiler option to /Ob2 and enable an optimization option. For example, you enable the /O1, /O2, or /Ox optimization option.

  • You build the project in the Release mode.

  • You run the generated application.

In this scenario, incorrect calculation results might be returned.


Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft website: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.


To apply this hotfix, you must have Microsoft Visual Studio 2010 Service Pack 1 (SP1) installed.

Restart requirement

You have to restart the computer if the affected files were being used when you installed this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix. 

File information

The global version of this 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.

File name

File version

File size











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

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

Thank you for your feedback!

Thank you for your feedback! It sounds like it might be helpful to connect you to one of our Office support agents.