The following two posts are discussing how to deal with a link error you see when you try to export a string class inherited from std::string. In the second post, some workarounds are also suggested.

1. http://social.msdn.microsoft.com/Forums/en/vcpluslanguage/thread/4238e162-21d2-46f6-a8f1-e1191cf1b200 → This page suddenly disappeared. I attached here its cache from Google.
2. https://connect.microsoft.com/VisualStudio/feedback/details/562448/std-string-npos-lnk2001-when-inheriting-a-dll-class-from-std-string?wa=wsignin1.0

If those workarounds do not work for you, you can try to link your binary to old libraries. Open the General Property Page of the project and set Platform Toolset to v90, instead of v100. → This works only if you installed Visual Studio 2008 as well.

I did some more experiments and found that the order of header files in the include statements do something with this. Sometimes the error disappears by just rearranging the order of headers. If it doesn’t work, try turning off the precompiled header option in the library exporting the string class.

From MSDN: http://msdn.microsoft.com/en-us/library/e2h7fzkw%28VS.100%29.aspx#uninstalling

To uninstall Visual Studio 2010

To uninstall Visual Studio, download and run the Microsoft Visual Studio 2010 Uninstall Utility (or download from this page). By default, this removes Visual Studio and supporting components, but does not remove components that are shared with other applications on the computer. To also remove shared components, run the uninstall utility with the /full switch. To also remove the .NET Framework 4, use the netfx switch. Uninstalling shared components or .NET Framework 4 may break earlier versions of Visual Studio or other applications that depend on.

If you cannot uninstall Visual Studio by using the uninstall utility, you can perform a manual uninstall by removing Visual Studio and then removing related components.

Continue…

Step 1. Uninstalling Visual Studio 2008

Some article suggests doing Step 2 first which is described below, but the order does not matter, to my experience. You can uninstall VS2008 by using one of the following channels.

• Add or Remove Programs (Windows Server 2003 and Windows XP) or Programs and Features (Windows Vista and Windows Server 2008)
• Setup.exe in the VS2008 installation media

When you do this, however, you may receive the following error message:

This problem occurs when you install an update that adds a new Windows Installer feature to VS2008, as described in Microsoft Knowledge Base article 959417 . To resolve this problem, patch VS2008 with the latest service pack. Install something to uninstall… Irony, huh?

Continue…