The specified account already exists - .NET Core RC2 tooling Preview 1

Question

Recently and with the release of Visual Studio 2015 Update 3 and .NET Core RTM, I decided to uninstall my previous installation of Visual Studio 2015 Update 2 and have a fresh installation of Update 3. So I uninstalled Visual Studio completely and restarted my PC.

Now I decided to uninstall the Microsoft .NET Core 1.0 RC2 VS 2015 Tooling Preview 1 from Control Panel. It gives me the following error several times and then fails:

The specified account already exists.

and here is the error code:

0x80070643 - Fatal error during installation

In the log file, these lines are repeated several times:

[1760:1CA0][2016-07-01T02:30:32]i301: Applying execute package: WebToolsExtensionsVS14, action: Uninstall, path: (null), arguments: ' ARPSYSTEMCOMPONENT="1" MSIFASTINSTALL="7" SKIP_SETUP="1"'
[1760:1CA0][2016-07-01T02:30:39]e000: Error 0x80070643: Failed to uninstall MSI package.
[1760:1CA0][2016-07-01T02:30:39]e000: Error 0x80070643: Failed to execute MSI package.
[247C:2490][2016-07-01T02:30:39]e000: Error 0x80070643: Failed to configure per-machine MSI package.
[247C:2490][2016-07-01T02:30:39]w348: Application requested retry of package: WebToolsExtensionsVS14, encountered error: 0x80070643. Retrying...

Answer 1

This is a bug in the .NET Core Tools for VS2015 installer.

I got this error when I tried to uninstall all VS2015 related tools on Windows 10 (not reinstallation, because I want VS2017 instead). I uninstalled VS2015 before removing .NET Core Tools. While trying to remove .NET Core Tools, it tried to call WebToolsExtensionsVS14 for repair; WebToolsExtensionsVS14 failed because VS2015 no longer existed.

I found the MSI package for WebToolsExtensionsV14 in the package cache:

C:\ProgramData\Package Cache\{BFC344B0-DCDE-36EB-AB05-CB194F2BE946}v14.1.21111.0\packages\WebToolsExtensionsVS14_69.msi

and right-click uninstalled it. Then the .NET Core Tools uninstaller worked.

My recommendation is to remove core tools before removing VS itself.

I found some related issue here, after I figured it out. https://social.msdn.microsoft.com/Forums/vstudio/en-US/ae380a17-60e0-43a4-a481-6e58915e7897/net-core-errors-on-installation-webtoolsextensionsvs14-encountered-error-0x80070643?forum=vssetup

Answer 2

As I said in the question, I had Visual Studio 2015 Update 2 uninstalled already, and couldn't uninstall the .NET Core tooling after that.

The fix was to INSTALL Visual Studio 2015 Update 3 and THEN uninstalling the .Net Core 1.0 Preview 1.

After that I successfully installed the Preview 2 version of the tooling and had no errors.