Visual C++ Compiler Nov 2013 CTP suddenly gone

today opened a project I was working on about 3 days ago and suddenly I get this message when trying to compile:

error MSB8020: The build tools for CTP_Nov2013 (Platform Toolset = 'CTP_Nov2013') cannot be found. To build using the CTP_Nov2013 build tools, please install CTP_Nov2013 build tools. Alternatively, you may upgrade to the current Visual Studio tools by selecting the Project menu or right-click the solution, and then selecting "Upgrade Solution...".

It does not make any sense to me. I use CTP Nov 2013 with VS2013 because I need some C++11 features not included in vanilla VS2013. There was no problem with it so far but since today (I haven't changed anything) I just cannot build the project.

I tried to install the CTP Nov 2013 again but during the installation I get error 0x80070666 that says the "another version of this product is already installed" (of course, I didn't uninstall it).

In the installation log there are these lines:

[0DB8:1B80][2015-10-12T10:57:48]i001: Burn v3.7.2002.0, Windows v6.1 (Build 7601: Service Pack 1), path: D:\Dokumenty\Download\vc_CompilerCTP.Nov2013.exe, cmdline: '' [0DB8:1B80][2015-10-12T10:57:48]i000: Setting string variable 'WixBundleLog' to value 'C:\Users\Aros\AppData\Local\Temp\dd_vc_CompilerCTPNov2013_20151012105748.log' [0DB8:1B80][2015-10-12T10:57:48]i000: Setting string variable 'WixBundleOriginalSource' to value 'D:\Dokumenty\Download\vc_CompilerCTP.Nov2013.exe' [0DB8:1B80][2015-10-12T10:57:48]i000: Setting string variable 'WixBundleName' to value 'Microsoft Visual C++ Compiler Nov 2013 CTP' [0DB8:1B80][2015-10-12T10:57:48]i100: Detect begin, 4 packages [0DB8:1B80][2015-10-12T10:57:48]i000: Setting string variable 'DevEnvAppIdKeyPath' to value 'C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\devenv.exe' [0DB8:1B80][2015-10-12T10:57:48]i000: Setting string variable 'VSWinExpressAppIdKeyPath' to value '' [0DB8:1B80][2015-10-12T10:57:48]i000: Setting string variable 'WDExpressAppIdKeyPath' to value '' [0DB8:1B80][2015-10-12T10:57:48]i102: Detected related bundle: {050d4fc8-5d48-4b8f-8972-47c82c46020f}, type: Upgrade, scope: PerMachine, version: 12.0.30501.0, operation: Downgrade [0DB8:1B80][2015-10-12T10:57:48]i101: Detected package: vc_CompilerCTP_x86, state: Absent, cached: None [0DB8:1B80][2015-10-12T10:57:48]i101: Detected package: vc_CompilerCTP_amd64, state: Absent, cached: None [0DB8:1B80][2015-10-12T10:57:48]i101: Detected package: vc_CompilerCTP_x86_arm, state: Absent, cached: None [0DB8:1B80][2015-10-12T10:57:48]i101: Detected package: vc_CompilerCTP_amd64_arm, state: Absent, cached: None [0DB8:1B80][2015-10-12T10:57:48]i052: Condition '( DevEnvAppIdKeyPath OR VSWinExpressAppIdKeyPath OR WDExpressAppIdKeyPath)' evaluates to true. [0DB8:1B80][2015-10-12T10:57:48]i199: Detect complete, result: 0x0 [0DB8:0D14][2015-10-12T10:57:53]e000: Error 0x80070666: Cannot install a product when a newer version is installed.

Well, it is not listed in "Programs and features", so I cannot even try to remove it... I also cannot find it on the disk, but that is probably because I don't know the target directory and cannot seem to google it. Searching for files containing "CTP", "compiler", "Nov" etc. shows no interesting results. Is there anything I could try?

I got the same problem today. I searched Windows registry for the UID from the log. Found a package called "Microsoft Visual C++ 2013 Redistributable (x64)". The CTP installer worked fine after I uninstalled that package.