Today my machine just woke up, with Typescript compilation error.
I get things like:
Error 2 The specified task executable location "C:\Program Files (x86)\Microsoft SDKs\TypeScript\tsc.exe" is invalid. UpgradeHelpers.WebMap.Client
Error 1 Your project file uses a different version of the TypeScript compiler and tools than is currently installed on this machine. No compiler was found at C:\Program Files (x86)\Microsoft SDKs\TypeScript\tsc.exe. You may be able to fix this problem by changing the <TypeScriptToolsVersion> element in your project file. UpgradeHelpers.WebMap.Client
All this seems to be related to installing VS 2015 Preview CTP6.
Also Typescript compilation in VS2013 stopped working.
The workaround is:
Run Repair for TypeScript 1.4 from Control Panel/Uninstall Programs.
You can find more details in