I tried to install objc-syntax-highlighting.vsix in visual studio 2017 community offline. I could not resolve it. I've downloaded extension package from https://github.com/Microsoft/WinObjC/releases and tried to install package from 0.2 Preview (December 2017)
2/21/2018 11:58:55 AM - Microsoft VSIX Installer 
2/21/2018 11:58:55 AM - -------------------------------------------
2/21/2018 11:58:55 AM - vsixinstaller.exe version:
2/21/2018 11:58:55 AM - 15.5.99+g87f89a485e
2/21/2018 11:58:55 AM - -------------------------------------------
2/21/2018 11:58:55 AM - Command line parameters:
2/21/2018 11:58:55 AM - C:\Program Files (x86)\Microsoft Visual Studio\Installer\resources\app\ServiceHub\Services\Microsoft.VisualStudio.Setup.Service\VSIXInstaller.exe,C:\Users\lenovo\AppData\Local\Temp\Rar$DIa10400.20842\objc-syntax-highlighting.vsix
2/21/2018 11:58:55 AM - -------------------------------------------
2/21/2018 11:58:55 AM - Microsoft VSIX Installer
2/21/2018 11:58:55 AM - -------------------------------------------
2/21/2018 11:58:58 AM - Initializing Install...
2/21/2018 11:58:58 AM - Extension Details...
2/21/2018 11:58:58 AM -     Identifier         : VSIX..9c35fff1-f084-44c1-a38e-68c707163aa2
2/21/2018 11:58:58 AM -     Name               : Objective-C Language Service
2/21/2018 11:58:58 AM -     Author             : Microsoft
2/21/2018 11:58:58 AM -     Version            : 1.5
2/21/2018 11:58:58 AM -     Description        : This package contains Objective-C language service components such as syntax higlighting etc
2/21/2018 11:58:58 AM -     Locale             : en-US
2/21/2018 11:58:58 AM -     MoreInfoURL        : 
2/21/2018 11:58:58 AM -     InstalledByMSI     : False
2/21/2018 11:58:58 AM -     SupportedFrameworkVersionRange : [4.5,)
2/21/2018 11:58:58 AM - 
2/21/2018 11:58:58 AM -     SignatureState     : Unsigned
2/21/2018 11:58:58 AM -     Supported Products : 
2/21/2018 11:58:58 AM -         Microsoft.VisualStudio.Community
2/21/2018 11:58:58 AM -             Version : [12.0,15.0)
2/21/2018 11:58:58 AM -         Microsoft.VisualStudio.Premium
2/21/2018 11:58:58 AM -             Version : [12.0,15.0)
2/21/2018 11:58:58 AM -         Microsoft.VisualStudio.Pro
2/21/2018 11:58:58 AM -             Version : [12.0,15.0)
2/21/2018 11:58:58 AM -         Microsoft.VisualStudio.Ultimate
2/21/2018 11:58:58 AM -             Version : [12.0,15.0)
2/21/2018 11:58:58 AM -         Microsoft.VisualStudio.Enterprise
2/21/2018 11:58:58 AM -             Version : [12.0,15.0)
2/21/2018 11:58:58 AM - 
2/21/2018 11:58:58 AM -     References         : 
2/21/2018 11:58:58 AM - Signature Details...
2/21/2018 11:58:58 AM -     Extension is not signed.
2/21/2018 11:58:58 AM - 
2/21/2018 11:58:58 AM - Searching for applicable products...
2/21/2018 11:58:58 AM - Found installed product - Global Location
2/21/2018 11:58:58 AM - Found installed product - Visual Studio Community 2017
2/21/2018 11:58:58 AM - VSIXInstaller.NoApplicableSKUsException: This extension is not installable on any currently installed products.
at VSIXInstaller.App.GetInstallableData(String vsixPath, Boolean isRepairSupported, IEnumerable`1& skuData)
at VSIXInstaller.App.Initialize(Boolean isRepairSupported)
at VSIXInstaller.App.Initialize()
at System.Threading.Tasks.Task`1.InnerInvoke()
at System.Threading.Tasks.Task.Execute()
Could anyone help me out this?