xmlexception:给定编码中的无效字符.1号线，1号位置.使用Nuget时

在过去的24小时内，Nuget似乎向我抛出了一个奇怪的错误。

每次我尝试安装或卸载一个包…如果失败，将显示以下错误:

System.Xml.XmlException: Invalid character in the given encoding. Line 1, position 1.

总堆栈为:

Attempting to gather dependencies information for package 'Microsoft.AspNet.WebApi.Client.5.2.3' with respect to project 'User Interface'SMRH.LPIC.Web', targeting '.NETFramework,Version=v4.5.1'
Attempting to resolve dependencies for package 'Microsoft.AspNet.WebApi.Client.5.2.3' with DependencyBehavior 'Lowest'
Resolving actions to install package 'Microsoft.AspNet.WebApi.Client.5.2.3'
Resolved actions to install package 'Microsoft.AspNet.WebApi.Client.5.2.3'
For adding package 'Microsoft.AspNet.WebApi.Client.5.2.3' to project 'SMRH.LPIC.Web' that targets 'net451'.
For adding package 'Microsoft.AspNet.WebApi.Client.5.2.3' to project    'SMRH.LPIC.Web' that targets 'net451'.
Package 'Microsoft.AspNet.WebApi.Client.5.2.3' already exists in folder   'F:'TFS'DevTeamCode'LPIC'SMRH.LPIC'packages'
Added reference 'System.Net.Http.Formatting' to project 'SMRH.LPIC.Web'.
Added package 'Microsoft.AspNet.WebApi.Client.5.2.3' to 'packages.config'
Successfully installed 'Microsoft.AspNet.WebApi.Client 5.2.3' to SMRH.LPIC.Web
Added file 'web.config'.
Install failed. Rolling back...
System.Xml.XmlException: Invalid character in the given encoding. Line 1, position 1.
at System.Xml.XmlTextReaderImpl.Throw(Exception e)
at System.Xml.XmlTextReaderImpl.Throw(String res, String arg)
at System.Xml.XmlTextReaderImpl.InvalidCharRecovery(Int32& bytesCount, Int32& charsCount)
at System.Xml.XmlTextReaderImpl.GetChars(Int32 maxCharsCount)
at System.Xml.XmlTextReaderImpl.ReadData()
at System.Xml.XmlTextReaderImpl.SwitchEncoding(Encoding newEncoding)
at System.Xml.XmlTextReaderImpl.SwitchEncodingToUTF8()
at System.Xml.XmlTextReaderImpl.ParseXmlDeclaration(Boolean isTextDecl)
at System.Xml.XmlTextReaderImpl.Read()
at System.Xml.Linq.XDocument.Load(XmlReader reader, LoadOptions options)
at NuGet.ProjectManagement.XmlUtility.LoadSafe(Stream input, LoadOptions options)
at NuGet.ProjectManagement.XmlUtility.GetDocument(String root, String path)
at NuGet.ProjectManagement.XmlUtility.GetOrCreateDocument(XName rootName, String root, String path, INuGetProjectContext nuGetProjectContext)
at NuGet.PackageManagement.VisualStudio.BindingRedirectManager.GetConfiguration()
at NuGet.PackageManagement.VisualStudio.BindingRedirectManager.AddBindingRedirects(IEnumerable`1 bindingRedirects)
at NuGet.PackageManagement.VisualStudio.RuntimeHelpers.<AddBindingRedirectsAsync>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at NuGet.PackageManagement.VisualStudio.RuntimeHelpers.<AddBindingRedirectsAsync>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at NuGet.PackageManagement.VisualStudio.RuntimeHelpers.<AddBindingRedirectsAsync>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at NuGet.PackageManagement.VisualStudio.RuntimeHelpers.<AddBindingRedirectsAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at NuGet.PackageManagement.VisualStudio.VSMSBuildNuGetProjectSystem.<<AddBindingRedirects>b__55_0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.VisualStudio.Threading.JoinableTask.CompleteOnCurrentThread()
at NuGet.PackageManagement.VisualStudio.VSMSBuildNuGetProjectSystem.AddBindingRedirects()
at NuGet.ProjectManagement.MSBuildNuGetProject.PostProcessAsync(INuGetProjectContext nuGetProjectContext, CancellationToken token)
at NuGet.PackageManagement.NuGetPackageManager.<ExecuteNuGetProjectActionsAsync>d__42.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at NuGet.PackageManagement.NuGetPackageManager.<ExecuteNuGetProjectActionsAsync>d__42.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at NuGet.PackageManagement.UI.UIActionEngine.<ExecuteActionsAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at NuGet.PackageManagement.UI.UIActionEngine.<PerformActionAsync>d__3.MoveNext()
========== Finished ==========

它不会告诉我它在哪个文件失败。删除packages文件夹并恢复它也不工作。

我在网上查过了。配置，它似乎没有格式问题。

重启PC和VS，但运气不好。

使用Visual Studio 2015 Enterprise，使用c#环境。