While you can still use the existing VS 2015 tooling previews for .NET Core and ASP.NET Core development, Visual Studio 2017 is now the officially supported tool for developing .NET Core and ASP.NET Core projects.
If you encounter any issues with VS 2015 not already listed below, you can report them using the Report a Problem tool on our Developer Community site, where you can track the status and see issues reported by others as well.
If you encounter a problem with Visual Studio, we want to know about it so that we can diagnose and fix it. By using the Report a Problem tool, you can collect detailed information about the problem, and send it to Microsoft with just a few button clicks. See Visual Studio’s Talk to Us page for more details. The GitHub Issue Tracker for the aspnet/Tooling repo is now deprecated in favor of the Report a Problem tool.
After installing Visual Studio 2017 on the same machine as Visual Studio 2015 with .NET Core tooling, restoring NuGet packages in an ASP.NET Core project using Visual Studio 2015 fails
On a machine that already has VS 2015 with .NET Core Tooling, if you install VS 2017 and then try to restore packages for an ASP.NET project using VS 2015, it might fail with the following error message:
MSBUILD : error MSB4025: The project file could not be loaded. Data at the root level is invalid. Line 1, position 1
Install the latest update for .NET Core VS 2015 tooling to resolve the above error. After installing this update, you will be able to restore NuGet packages again using VS 2015.
If you open or create a .NET Core project project and Visual Studio cannot find the corresponding .NET Core SDK, you'll get a dialog box similar to the following:
This occurs if:
This is caused by Visual Studio 2017 RC installing both the x86 and x64 versions of the .NET Core SDK. To workaround the issue, edit your PATH environment variable to only point to the version of the SDK that matches your operating system architecture (e.g. if your operating system is x64, remove the entry from the PATH that points to "C:\Program Files (x86)\dotnet")
To workaround this you can install the correct version of the .NET SDK. You can use the links below.
| Platform | Link |
|---|---|
| Windows x64 | https://go.microsoft.com/fwlink/?LinkID=830694 |
| Windows x86 | https://go.microsoft.com/fwlink/?LinkID=830695 |
| Platform | Link |
|---|---|
| Windows x64 | https://go.microsoft.com/fwlink/?LinkID=809122 |
| Windows x86 | https://go.microsoft.com/fwlink/?LinkID=809123 |
| Platform | Link |
|---|---|
| Windows x64 | https://go.microsoft.com/fwlink/?LinkID=798398 |
| Windows x86 | https://go.microsoft.com/fwlink/?LinkID=798399 |
● Issue: IntelliSense adds extra characters in certain circumstances
In the Razor editor, if you type @ then some C# code, and you commit statement completion with the word fully typed out, additional characters will get added to the editor. For example, if you type @while then tab or space, an extra "while" will get added to the editor.
Workaround: Either do not type out the whole word, or dismiss statement completion.
Fix: We are working on a fix and will be delivered as an update to Visual Studio Update 3.
● Issue:Error on uninstall when the original installer has been deleted. In some cases if you have previously installed ".NET Core RC2 Tooling Preview 1" or "ASP.NET 5 RC1" and you try to uninstall it, you might run into the following dialog. This can happen if you previously downloaded the installer to the Downloads folder but it's not there anymore.
Workaround: Download the original installer and use that to uninstall link. Download links below.
- RC2 (1.0.20513.14)
- RC1 U1 we shipped for Visual Studio as part of an updated Web Developer Tools (1.0.20204.0)
- RC1 U1 we shipped for Azure SDK 2.8 (1.0.11125.0)
- RC1 U1 (1.0.11123.0)
- RC1 (without U1) (1.0.11117.0) (original download page available here)
● Issue:After installing the tooling, you might run into the following dialog when trying to create a project. This is due to an issue in Visual Studio 2015 Update 3 setup that sometimes caused stale entries in the devenv.exe.config file.
Workaround:
- Close Visual Studio
- Delete the
C:\Users\<user>\AppData\Local\Microsoft\VisualStudio\14.0\devenv.exe.configfile. - Run the Developer Command Prompt for VS2015 as the Administrator, and execute the
devenv /setupcommand.
● Issue:Setup failed: another version already installed In some cases you may get an error dialog on setup with an error message "0x80070666 - Another version of this product is already installed."
Workaround: See the Known issues page for Visual Studio 2015 Update 3 RC for additional details.
● Issue:Multiple entries found in Add Remove Programs When upgrading tooling, previous versions continue to show up in Add/Remove Programs. This typically happens when the previous bundle is being removed as part of the upgrade and fails to locate the original source of the installer. The log files for the uninstall would contain entries similar to this
[47B8:0798][2016-06-24T18:36:44]w210: Plan skipped due to 1 remaining dependents
[47B8:0798][2016-06-24T18:36:44]i207: Planned related bundle: {58140f9c-9a01-4e20-bc5f-8ca652fd3ec4}, type: Upgrade, default requested: None, ba requested: None, execute: None, rollback: None, dependency: None
Workaround: Leaving the previous bundle in Add/Remove Programs should not cause any problems. You can remove it by following the steps below. Note: these steps require registry updates, please use caution.
- Open REGEDIT
- Under
HKCR\Installers\Dependenciesfind subkeys using the GUIDs from the log messages. For example from the log aboveHKCR\Installers\Dependencies\{GUID}\Dependents\{58140f9c-9a01-4e20-bc5f-8ca652fd3ec4} - Only delete the highlighted registry key above and run the uninstall again
● Issue: Variables not appearing in debugger for Razor views During debugging, when you hit a breakpoint in C# code in a Razor page, you cannot get information about variables in the watch window.
Workaround: None
Fix: We are working on a fix and will be delivered as an update to Visual Studio Update 3.
● Issue: IIS Express fails start after copying a project/solution from one folder to another.
Workaround: Close all instances of Visual Studio and delete the .vs folder.
Fix: We are working on a fix to be included in a future release of .NET Core Tooling.
● Issue: Poor error experience for "Can not find runtime target framework" In some cases you may see multiple errors relating to "Can not find runtime target for framework..."
Workaround: None
Fix: We are investigating.
● Issue: Errors shown in project.json for valid packages
In some cases when the project.json file is open in the editor it will show errors for packages which were restored fine. The exact details are still under investigation.
Workaround: You can ignore the squiggles and error messages for these packages.
Fix: We are investigating.
● Issue: Package cache executes on first EF migration command
When you run dotnet ef migrations or other dotnet commands, you might see that it takes a while for dotnet CLI to populate the local package cache. This is expected and should only happen one-time per user on the machine.
Workaround: There is no impact after the initial delay.
Fix: We are investigating.
● Issue: Running dotnet ef from command-line fails when IIS Express is running
When working with ef migrations from the command line, for example, when running a command like dotnet ef migrations add Initial you may get an error similar to the following.
C:\3\MvcMovie\src\MvcMovie>dotnet ef migrations add Initial
Project MvcMovie (.NETCoreApp,Version=v1.0) will be compiled because project is not safe for incremental compilation. Use --build-profile flag for more information.
Compiling MvcMovie for .NETCoreApp,Version=v1.0
C:\Program Files\dotnet\dotnet.exe compile-csc @C:\3\MvcMovie\src\MvcMovie\obj\Debug\netcoreapp1.0\dotnet-compile.rsp returned Exit Code 1
Compilation failed.
C:\3\MvcMovie\src\MvcMovie\error CS2012: Cannot open 'C:\3\MvcMovie\src\MvcMovie\bin\Debug\netcoreapp1.0\MvcMovie.dll' for writing -- 'The process cannot access the file 'C:\3\MvcMovie\src\MvcMovie\bin\Debug\netcoreapp1.0\MvcMovie.dll' because it is being used by another process.'
0 Warning(s)
1 Error(s)
Time elapsed 00:00:04.3201268
Build failed on 'MvcMovie'.
Workaround: : Exit IIS Express from the system tray. This will unlock the dll and allow the command to run.
Fix: We are investigating.
● Issue: Errors when publishing with EF migrations on Windows 7 If you publish a web project with EF migrations on Windows 7 you may get an error due to missing commands. This is because the current script uses features which require PowerShell v3.
Workaround: Install PowerShell v3
Fix: We are working on a fix which should be included in a future release of .NET Core Tooling.
● Issue: Register functionality of app fails if EF Migrations were not applied After publishing a project that includes authentication, the app will fail to run if EF Migrations were not applied on publish.
Workaround: Update the publish profile to execute EF Migrations. This can be found on the Settings tab of the Publish Web dialog.
● Issue: Compiler error while scaffolding an MVC controller In some cases you may get an error dialog when scaffolding.
---------------------------
Microsoft Visual Studio
---------------------------
Error
There was an error running the selected code generator:
'Project WebApplication6 (.NETCoreApp,Version=v1.0) will be compiled because project is not safe for incremental compilation. Use --build-profile flag for more information.
Compiling WebApplication6 for .NETCoreApp,Version=v1.0
Running with configuration from C:\temp\WebApplication6\src\WebApplication6\bundleconfig.json
Processing wwwroot/css/site.min.css
Bundled
Minified
Processing wwwroot/js/site.min.js
Compilation failed.
0 Warning(s)
1 Error(s)
Time elapsed 00:00:05.9348301'
---------------------------
OK
---------------------------
Workaround: Retry scaffolding
Fix: We are investigating
● Issue: Bad experience scaffolding when the project fails to build. Scaffolding output doesn't contain the compilation errors if the project compilation fails during scaffolding. For example here is the actual output.
Build Failed
Project WebApplication8 (.NETCoreApp,Version=v1.0) will be compiled because project is not safe for incremental compilation. Use --build-profile flag for more information.
Compiling WebApplication8 for .NETCoreApp,Version=v1.0
RunTime 00:00:08.53
Running with configuration from C:\Users\fwtlaba\Documents\Visual Studio 2015\Projects\WebApplication8\src\WebApplication8\bundleconfig.json
Processing wwwroot/css/site.min.css
Bundled
Minified
Processing wwwroot/js/site.min.js
Compilation failed.
0 Warning(s)
1 Error(s)
Time elapsed 00:00:06.6119118
And the expected output.
Build Failed
Project WebApplication8 (.NETCoreApp,Version=v1.0) will be compiled because project is not safe for incremental compilation. Use --build-profile flag for more information.
Compiling WebApplication8 for .NETCoreApp,Version=v1.0
Running with configuration from C:\Users\fwtlaba\Documents\Visual Studio 2015\Projects\WebApplication8\src\WebApplication8\bundleconfig.json
Processing wwwroot/css/site.min.css
Bundled
Minified
Processing wwwroot/js/site.min.js
C:\Program Files\dotnet\dotnet.exe compile-csc @C:\Users\fwtlaba\Documents\Visual Studio 2015\Projects\WebApplication8\src\WebApplication8\obj\Debug\netcoreapp1.0\dotnet-compile.rsp returned Exit Code 1
C:\Users\fwtlaba\Documents\Visual Studio 2015\Projects\WebApplication8\src\WebApplication8\Program.cs(21,23): error CS1002: ; expected
Compilation failed.
0 Warning(s)
1 Error(s)
Time elapsed 00:00:09.4108500
Workaround: None
Fix: We are investigating.
● Issue: Scaffolding MVC w/views assumes the presence of _ValidationScriptsPartial.cshtml When scaffolding a new MVC controller with views using Entity Framework, the Create and Edit views reference _ValidationScriptsPartial.cshtml, which is only included in the Individual Auth template, causing this error in other templates:
InvalidOperationException: The partial view '_ValidationScriptsPartial' was not found. The following locations were searched:
/Views/Movies/_ValidationScriptsPartial.cshtml
/Views/Shared/_ValidationScriptsPartial.cshtml
Workaround: Copy _ValidationScriptsPartial.cshtml from a new project.
Fix: We are investigating.
● Issue: Connection string is added in a different location than the templates If you use scaffolding to create a dbcontext while creating a controller it will add a connection string to appsettings.json and the code to read it in ConfigureServices. However, it's still using the location and APIs that were used in the RC1 templates and does not match the RC2 or RTM templates.
Workaround: After scaffolding move the connection string to the desired location.
Fix: We are working on a fix which should be included in a future version of .NET Core Tooling.
● Issue: Scaffolding fails when model class is in a different project. Scaffolding fails if model class is in a dependency (project/ library) of the project on which scaffolding is being run.
Workaround: None
Fix: We are investigating.
Known issues in this release.
Note: There is a known issue with Visual Studio 2015 Update 3 RC, as a result of which, .NET Core 1.0.0 RC2 - VS 2015 Tooling Preview 1 may fail to install after Visual Studio 2015 Update 3 RC is installed. See here for additional details and workaround.
In some cases the Add New Item dialog will select the wrong item by default. For example with the PowerShell tools installed when you start Add New Item one of the PowerShell templates may be selected by default. This is also impacting the Add Class menu option.
In some cases the Unhandled Exception dialog does not appear when it should.
Scaffolding is currently limited to the Web template with Individual Authentication. We are hoping to support scaffolding for all projects in the next release.
Currently the scaffolding feature directly embeds the connection string into code. This doesn't work well if you also use the EF Migrations publish feature. To get these two to work well together, move the connection string from code into the appsettings.json file.
The shared framework is not available in Azure Web Apps yet. We are working on getting it included.
When publishing an RC1 project with RC2 tooling, source files will be published even if you checked the "No Source" checkbox in RC1. To change to publishing binaries you'll need to modify the publish profile (.pubxml file under Properties\PublishProfiles) to include the following. For details on the workaround see http://stackoverflow.com/a/37425515.
In some cases the target runtime debug dropdown doesn't get populated correctly.
The web publish dialog always shows appsettings.production.json as being deleted even when it will not.
In some cases after publishing a project using Org Auth, the published application may fail to run.
In some cases all dependencies are not copied to the output folder.
You may get an error when using Work and School accounts and AI.
More info: aspnet/Templates#569
Microsoft.VisualStudio.Web.BrowserLink.Loader package cannot be loaded in a signed web application. app.UseBrowserLink() must be removed for the application to run.
Having property page open and modifying properties in project.json doesn't update property page
IIS express shows up as an option in the Launch drop down on Debug page for Console Application
There are some issues when using an .xproj referencing a .csproj.
All outputs may not be copied to the output folder. For example when using reference assemblies.
Roslyn #10471 - Portable Class library - > Platform target 'AnyCPU' is not supported by one or more of the project's targets.
dotnet cli #2961 - Runtime error after add reference from xproj web app (netcoreapp) to PCL csproj with project.json (netstandard)
Here are the known issues with ASP.NET 5 RC1
-
If you install ASP.NET 5 RC1 on a machine without Visual Studio 2015, then install Visual Studio 2015 later, you will need to repair 'ASP.NET 5 RC1' in Add/Remove programs to get tooling support in Visual Studio 2015 for ASP.NET 5 RC1
-
If you install ASP.NET 5 RC1 on a machine that already has Visual Studio 2015, then install a VS 2015 language pack, you will need to repair 'ASP.NET 5 RC1' in Add/Remove programs to get tooling support in Visual Studio for web projects
-
After installing RC1 Update 1, Browser Link may be disabled in DNX projects that are created after the installation. If the Browser Link Dashboard displays "No current connections" when running or debugging a DNX project a repair of the update will correct the issue:
- Close Visual Studio
- Open Control Panel > Uninstall a Program
- Right click on "Microsoft ASP.NET 5 RC1 Update 1"
- Click "change"
- In the ASP.NET 5 RC1 Update 1 Installer, click "Repair"
-
Visual Studio keeps showing suggested extensions in the yellow info bar when opening an HTML file. It also shows an error message when there are Git merge conflicts or with Annotate and Excluded Folder documents. More details here.
Here are the known issues with ASP.NET 5 Beta8
Visual Studio caches some of it's internal state in the ComponentModelCache folder. In some cases this cache may be invalidated, but not updated correctly. The result is that you may run into a number of errors which cannot be explained directly.
For example any of the following error messages could indicate an issue with an invalid ComponentModelCache.
System.ArgumentException: Item has already been added. Key in dictionary: 'RazorSupportedRuntimeVersion'
This project is incompatible with the current edition of Visual Studio:
Microsoft Visual Studio Community 2015 Version 14.0.23107.0 D14REL
Microsoft .NET Framework
Version 4.6.00079
Workaround
To work around this.
- Close all instances of Visual Studio
- Delete the folder at
%localappdata%\Microsoft\VisualStudio\14.0\ComponentModelCache - Restart Visual Studio
If you experience any issues with NuGet packages not being resolved, or being resolved to unexpected versions. The best thing to try install the latest version of NuGet from https://visualstudiogallery.msdn.microsoft.com/5d345edc-2e2d-4a9c-b73b-d53956dc458d/file/146283/8/NuGet.Tools.vsix.
Some examples off issues that may be resolved by updating NuGet are below.
- NuGet feed for nuget.org is disabled
- Package restore returns
beta8packages instead ofbeta5packages
With ASP.NET 5 Beta8 we have changed how web applications are hosted with the Visual Studio debugger. In this release when you stop debugging you may notice there is a system beep that occurs at the end of debugging. This is a known issue that should be fixed with the first update for Visual Studio 2015 itself. The only workaround is to disable system sounds for this release. There is no functional impact.
Sometimes, after you create an ASP.NET Web Application project for the first time, when you hit F5 for the first time, iisexpress.exe will exit with error code 666.
Workaround
If you run into this error you should be able to hit F5 again to get the project to launch correctly.
In some cases, when creating an ASP.NET 5 project, DNVM fails to install the DNX runtime, and you will see the following error in the DNVM log:
Installing to C:\Users\balach\.dnx\runtimes\dnx-clr-win-x86.1.0.0-beta6
Move-Item : Access to the path 'C:\Users\balach\.dnx\runtimes\temp\dnx-clr-win-x86.1.0.0-beta6' is denied.
At C:\Program Files\Microsoft DNX\Dnvm\dnvm.ps1:1156 char:17
+ Move-Item $UnpackFolder $RuntimeFolder
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : WriteError: (C:\Users\balach...x86.1.0.0-beta6:DirectoryInfo) [Move-Item], IOException
+ FullyQualifiedErrorId : MoveDirectoryItemIOError,Microsoft.PowerShell.Commands.MoveItemCommand
Cannot find dnx-clr-win-x86.1.0.0-beta6, do you need to run 'dnvm install 1.0.0-beta6'?
At C:\Program Files\Microsoft DNX\Dnvm\dnvm.ps1:1268 char:9
+ throw "Cannot find $runtimeFullName, do you need to run '$Com ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : OperationStopped: (Cannot find dnx...l 1.0.0-beta6'?:String) [], RuntimeException
+ FullyQualifiedErrorId : Cannot find dnx-clr-win-x86.1.0.0-beta6, do you need to run 'dnvm install 1.0.0-beta6'?
Installing to C:\Users\balach\.dnx\runtimes\dnx-coreclr-win-x86.1.0.0-beta6
Adding C:\Users\balach\.dnx\runtimes\dnx-coreclr-win-x86.1.0.0-beta6\bin to process PATH
Compiling native images for dnx-coreclr-win-x86.1.0.0-beta6 to improve startup performance...
Workaround
Restart Visual Studio and try creating the project again. DNVM should succeed this time.
If you update your ASP.NET 5 web project to target only CoreCLR (only dnxcore50 in project.json), you might run into the following failure when you try to Publish with the default Publish settings.
The "Dnu" task failed unexpectedly.
The project being published does not support the runtime 'dnx-clr-win-x86.1.0.0-beta6'
Workaround
In the Settings tab of the Publish dialog, explicitly select dnx-coreclr as the target rather than using the 'Default'. See the image below.
The applicationHost.config file will sometimes appear as an untracked file in Solution Explorer. This file should not be checked in as it has user specific paths which will not work in team environments.
Removing dnx451 from project.json frameworks may lead to erroneous build errors for ASP.NET 5 Web Sites projects
If you remove the dnx451 value from the frameworks section in project.json for ASP.NET 5 Web Site projects you may receive an error similar to "The type or namespace name 'AspNet' does not exist in the namespace 'Microsoft' (are you missing an assembly reference?)". To work around this you can remove the file at Compiler\Preprocess\RazorPreCompilation.cs.
Unable to add a reference to a standard C# project (.csproj) from an ASP.NET 5 project which is missing global.json
If you are working in a solution with ASP.NET 5 projects that does not have a global.json file you may not be able to add a reference to a standard C# project (.csproj) from an ASP.NET 5 project.
If you install an x64 CoreClr version of dnvm and use that as the default then you may get error message like "Cannot find the DNX runtime '' … ". To work around this install the corresponding x86 version as well.
When publishing using Visual Studio 2015 Web Express you may receive an error like "The InstallDir property does not exist in the path HKEY_LOCAL_MACHINE\SOFTWARE\ Wow6432Node\Microsoft\VisualStudio\14.0." Even though this error is reported in most cases the site is actually published.
If you are using a localized version of Visual Studio 2015 IntelliSense for version of bower packages may not work in bower.json.