I faced the problem: whenever I open my working solution Visual Studio automatically starts build. I cannot find configurations to turn off this.
It looks like that problem is in solution, because I opened another solution and build did not start automatically.
This strange behavior is not expected one for VS2019. Please try:
1.Tools=>Import and Export Settings=>Reset all settings=>No, just reset settings to reset current VS settings to default.
2.Use vs installer to repair your VS if there's something broken with IDE.
3.Extensions=>Manage Extensions=>Installed=>Tools you can disable(don't need to uninstall) some third-party extensions and restart VS to check if this issue persists. To check if this issue is about VS itself or extensions.
4.Exit VS and delete the .vs, bin, obj folders of the projects in the solution, and then clear the cache, for VS2019, the corresponding folder is 16.0 instead of 14.0. After that, restart VS.
For me, this was a Resharper setting. When I turned this off it stopped happening. I think there is also a setting for Visual Studio to do this as well, but it is off by default.
I've installed the newly released version of Visual Studio 2017 and started a fresh ASP.NET Core project targeting .NET Core.
Out of the box, I'm getting the
The type or namespace name 'System' could not be found (are you
missing a using directive or an assembly reference?)
error. Any idea what's causing this and how to fix it?
Also, looks like there are problems with NuGet packages as well:
I also tried dotnet restore on the project through the command line and got the following error:
P.S. Kind of disheartening that you get an error in a fresh new project in the latest version of Visual Studio 2017!
UPDATE:
SDK version is v 1.0.1 -- see below:
UPDATE 2:
This is very strange. Looks like the original problem was due to NuGet package source pointing to a folder under Visual Studio 2015 folder. I unchecked it and left only nuget.org. With that my project seemed to have restored all the packages and when I started the project it loads up the standard ASP.NET page. But if I open startup.cs file, I get red squigglies all over the place but if I run the project, it works fine. What's going on here?
UPDATE 3:
I closed the project and VS 2017. I then restarted VS 2017 and opened the project and now it seems to be fine. And I'm not referencing the .NETStandard library 1.6.1 and everything seems to be working fine now.
I had the same issue in my Visual studio 2017 .Net Core application. I closed the Visual studio and re-open fixed everything.
Came across the same issue today. I had an old nuget source that no longer existed. So I went into Tools > Nuget Packet Manager and un-checked the wrong one. Hit "Ok", and then rebuilt the project, and it works great now. It seems like you stumbled onto it, but also wanted to verify that it fixed my issue, and it does.
I had the same problem, first when converting a VS2015 net core mvc web project to 2017 and then when trying to create a new core web application in 2017.
Went to Tools|NuGet Package Manager|Package Manager Settings - checked 'Allow NuGet to download missing packages' and 'Automatically check for missing packages during build in VS' and then clicked 'Clear All NuGet Cache(s)'.
Then re-built the solution - it found and loaded all the required packages and ran OK.
May not work for all cases but simple and worth a try.
Multiple closing and reopening of VS2017 fixed it for me.
I had the same issue, the solution for me was to clear the NuGet cache. Tools > NuGet Package Manager > Package Manager Settings > Clear All NuGet Cache(s)
Check the version .NET Command Line Tools in CMD, just type dotnet --info. If version is 1.0.0, then try to install latest version .NET Core SDK from here.
Find the broken project and right click, Unload, right click, Re-load. Fastest fix for me.
If you get the problem while using the CLI, try doing nuget restore instead of dotnet restore as that sometimes pulls down packages that the dotnet CLI seems to miss.
I have had the same issue with Visual Studio 2019 and .NET Core SDK 2.2.
These steps solved the problem:
Close the Visual Studio
Open the Visual Studio as Administrator
Open the Solution
Right click on Solution -> Restore NuGet Packages
I've tried all answers above. For me works only removal and adding the reference again described in the following steps:
Open 'References' under the project.
Right click on 'System' reference.
Click on 'Remove'.
Right click on 'References'.
Click 'Add Reference...'.
From right menu choose an 'Assemblies',
In a search field type 'System'.
Choose 'System' from the list.
Click 'Add' button.
IMPORTANT: Restart the Visual Studio.
'System' reference you can replace with any you need.
Try adding the following line above the other references in the csproj file
<Reference Include="netstandard" />
For me the problem was caused by my project having a custom IntermediateOutputPath. For some reason, if project_name.csproj.nuget.g.targets is not in obj subfolder of project folder, the error occurs.
Using default IntermediateOutputPath or keeping a shadow copy of project_name.csproj.nuget.g.targets in fake obj folder solves the problem for me.
This issue seems to be triggered by a myriad of reasons. Mine was caused by cloning directly from VSTS using Git Bash, my project directory had spaces in it. Git Bash changed those spaces in the path to %20. It was throwing off all the references in my project. So for anyone who tried everything else and are at their wits end, make sure %20 is not in the path.
So, I have cloned the repository from github and started getting this error.
It was my project uploaded from another machine. I later realized that I have used the materialdesign packages in my project.
I have uninstalled and reinstalled these packages and it fixed my issue.
Had the same problem. Uninstalled Application Insights from my projects using the nuget package manager. I'm not looking at that yet, I just wanted core and unit tests. Problem solved.
I also had the same problem.
The is no SDK folder under the Dependencies one. Therefore, no Microsoft.NetCore.App libraries !
To solve this problem, in Nuget manager window, install any nuget which depends on .NetCoreApp (you can install for example Microsoft.AspNetCore or BundlerMinifier.Core from the Microsoft Visual Studio Offline Packages source).
The SDK will be restored by the same time.
Once it is back, you can uninstall the previously added nuget. The SDK will remain in place.
Not quite sure in which order vs 2017 trying to resolve packages.
But my situation was following. In my VS2015 I had configured local and 3rd party source for nuget packages, newly installed version of 2017 loaded them too.
https://api.nuget.org/v3/index.json was first in list.
But vs2017 throwed an error that it can't restore .net core libraries from my another local repo.
After I unchecked all of them except https://api.nuget.org/v3/index.json, it had started to working normally.
I had this problem too, but not right now, this steps solved my problem: Choose Project -> Properties from the menu bar. In the Project properties window, under Configuration Properties -> General, make sure that Common Language Runtime Support is set to Common Language Runtime Support (/clr)
Simply opening the NuGet package manager and then the Visual Studio settings related to it - without changing anything - merely looking around, and when I closed out, the problem was gone.
This seems to be an intermittent issue that can come and go for no obvious reason.
None of the answers here worked for me so I'm posting what did work.
My errors were mostly the same as the original poster but I also had:
Error loading meta data for 'Microsoft.Extensions.FileProviders.Embedded.2.0.1'
hexadecimal value 0x1C invalid character
Every time I attempted to download a different nuget package or restore old packages I would see this error. I also saw the other errors such as:
type or namespace system could not be found
What worked for me:
opened the filepath that the error said the bad metadata was in, which for me was C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.extensions.fileproviders.embedded\2.0.1
Then, I put the contents of that folder into another folder I named "hiding".
Then, I went back to the nuget package manager and tried to install a package, hoping to have the SDK restored. IOt worked successfully, and all my other errors were gone as well, and the fresh new project runs as it should!
The problem for me occurred when running my Visual Studio as Admin with a separate user-- I had created a Git Repo with the source files in the user documents of my normal account. When I created a new solution in that folder the above errors occurred. Try creating your project in a different place and see if the error still occurs.
I was facing the same issue when I created a new project (.net Core 2.2) in VS2019.In my case there was an Azure package which was creating the problem.I uninstalled it and the project started working fine.
Run mentioned below command to uninstall the package.
Uninstall-Package Microsoft.VisualStudio.Azure.Containers.Tools.Targets -Version 1.7.10
I had the same problem. I cloned a github project and this error came. So I deleted the cloned project and then I cloned the project again and it worked fine.
I'm trying to get our build server (TeamCity 8) to build an F# project (the first any of us have ever created on my team).
When I first ran the build I got the following error:
The value "" of the "Project" attribute in element <Import> is invalid. Parameter "path" cannot have zero length.
I assume that this means that the requisite F# tools are not present on the build server. I tried to rectify this using instructions on this blog post: http://www.heartysoft.com/ashic/blog/2013/3/build-fsharp-3-on-build-server-without-vs (summary: download and install VWD_FSharp.msi) but the problem persisted. I then added Condition="Exists('$(FSharpTargetsPath)')" to the Import tag in the fsproj so that it now reads:
<Import Project="$(FSharpTargetsPath)" Condition="Exists('$(FSharpTargetsPath)')" />
which I saw in another blog post, but all that's done is swapped the earlier error for a new one:
The target "Rebuild" does not exist in the project.
Any help here would be greatly appreciated; I really don't want to install VS on the build server. The only thing about our environment that might be noteworthy is that we're on .NET 4 rather than 4.5.
Thanks
Thanks for your question Ganesh, I have since solved the problem.
So, installing the F# tools using the link in my question did work, but after some digging round in the MSBuild directories it turns out that it only installed F# v3; my projects were targeting v3.1 (the default version in VS2013).
Going into each project's settings file and retargeting for 3.0 solved the problem.
currently i have changed the OS to windows 8 from Windows 7. While automation running 2005 project which refers LC.exe, wont compile successfully. But manually if i compile those project, get compiled.
please find the error i got while run those project from command prompt and also automating.
C:\Windows\Microsoft.NET\Framework\v2.0.50727\Microsoft.Common.targets(1679,9): error MSB3091: Task failed because "LC.exe" was not found, or the .NET Framework SDK v2.0 is not installed. The task is looking for "LC.exe" in the "bin" subdirectory beneath the location specified in the SDKInstallRootv2.0 value of the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft.NETFramework. You may be able to solve the problem by doing one of the following: 1.) Install the .NET Framework SDK v2.0. 2.) Manually set the above registry key to the correct location. 3.) Pass the correct location into the "ToolPath" parameter of the task.
Can anyone please help me ?
Re installing the .net framework 2.0 SDK would resolve this issue.
Framework SDK 2.0 refused to re-install on my machine but I was able to fix this by mucking about in the registry.
I have a Build server which has TFS 2010 Build Service installed. I have 2 Build Agents and 1 Controllers configured. One of our projects have been converted to Visual Studio 2012.
I found out that .NET framework 4.5 comes with new version of MSBuild which is version 4.5.
I installed .NET framework 4.5 on the Build Server because prior to installing it every time the project was built I kept getting the following error:
"Solution is of version '12.00' which is not currently supported".
After installing .NET 4.5, I still run into the same issue.
How could I go about resolving this?
Do I have to configure the Build Agent to use the new MSBuild 4.5 in order to build this particular project or do I set something in the projects solution file itself? If so how?
I would really appreciate if somebody could assist me with this please?
Try install vs2012 on the build server, while i don't believe it's strictly needed it's the easiest way to get all the requirements installed.
We have installed VS2012 on the build agent. Interestingly when I RDC to the build agent and then run msbuild from the command line everything works fine. So the issue looks like it happens before we even get to MSBuild.