更新至Visual Studio 2022 17.5.4后所有项目无法加载求助

我最近将Visual Studio 2022从17.4.5版本更新至17.5.4版本，更新完成后所有项目均无法加载。我已尝试修复安装程序，也卸载重装了最新版本及旧版本，但问题仍未解决，恳请提供帮助。

错误日志如下：

error  : SDK Resolver Failure: "The SDK resolver "Microsoft.DotNet.MSBuildSdkResolver" failed while attempting to resolve the SDK "Microsoft.NET.Sdk". Exception: "System.FormatException: Invalid numeric identifier: '300_bak'.
   at Microsoft.Deployment.DotNet.Releases.ReleaseVersion.TryParseCoreVersionPart(String input, Boolean throwOnFailure, Int32& value)
   at Microsoft.Deployment.DotNet.Releases.ReleaseVersion.TryParse(String input, Boolean throwOnFailure, ReleaseVersion& version)
   at Microsoft.Deployment.DotNet.Releases.ReleaseVersion.Parse(String input)
   at Microsoft.Deployment.DotNet.Releases.ReleaseVersion..ctor(String version)
   at Microsoft.NET.Sdk.WorkloadManifestReader.SdkFeatureBand..ctor(String version)
   at Microsoft.NET.Sdk.WorkloadManifestReader.SdkDirectoryWorkloadManifestProvider.<>c.<FallbackForMissingManifest>b__9_1(String featureBand)
   at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
   at System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
   at System.Linq.Enumerable.Max[TSource](IEnumerable`1 source)
   at Microsoft.NET.Sdk.WorkloadManifestReader.SdkDirectoryWorkloadManifestProvider.FallbackForMissingManifest(String manifestId)
   at Microsoft.NET.Sdk.WorkloadManifestReader.SdkDirectoryWorkloadManifestProvider.GetManifestDirectories()
   at Microsoft.NET.Sdk.WorkloadManifestReader.SdkDirectoryWorkloadManifestProvider.<GetManifests>d__7.MoveNext()
   at Microsoft.NET.Sdk.WorkloadManifestReader.WorkloadResolver.LoadManifestsFromProvider(IWorkloadManifestProvider manifestProvider)
   at Microsoft.NET.Sdk.WorkloadManifestReader.WorkloadResolver.Create(IWorkloadManifestProvider manifestProvider, String dotnetRootPath, String sdkVersion, String userProfileDir)
   at Microsoft.NET.Sdk.WorkloadMSBuildSdkResolver.CachingWorkloadResolver.Resolve(String sdkReferenceName, String dotnetRootPath, String sdkVersion, String userProfileDir)
   at Microsoft.DotNet.MSBuildSdkResolver.DotNetMSBuildSdkResolver.Resolve(SdkReference sdkReference, SdkResolverContext context, SdkResultFactory factory)
   at Microsoft.Build.BackEnd.SdkResolution.SdkResolverService.TryResolveSdkUsingSpecifiedResolvers(IList`1 resolvers, Int32 submissionId, SdkReference sdk, LoggingContext loggingContext, ElementLocation sdkReferenceLocation, String solutionPath, String projectPath, Boolean interactive, Boolean isRunningInVisualStudio, SdkResult& sdkResult)

问题根源 #

错误日志中明确指出Invalid numeric identifier: '300_bak'，这是因为.NET SDK的工作负载清单目录中存在命名不符合版本规范的备份文件夹（带_bak后缀），导致SDK版本解析逻辑无法识别该目录，进而引发项目加载失败。

修复步骤 #

• 打开.NET SDK的工作清单目录，默认路径：
  • 64位系统：C:\Program Files\dotnet\sdk-manifests
  • 32位系统：C:\Program Files (x86)\dotnet\sdk-manifests
• 在该目录下找到所有带有_bak后缀的文件夹（如日志中的300_bak），直接删除这些文件夹，或者将后缀修改为非下划线格式（例如300-bak）
• 同时检查用户目录下的SDK缓存路径：%USERPROFILE%\.dotnet\sdk-manifests，若存在类似命名的文件夹，执行同样操作
• 重启Visual Studio，重新加载项目

额外排查步骤（若上述方法无效） #

• 关闭Visual Studio，删除%LOCALAPPDATA%\Microsoft\VisualStudio\<你的VS版本号>\ComponentModelCache目录下的所有文件，清除组件缓存后重启VS
• 打开命令提示符，执行dotnet workload list命令，检查是否有异常的工作负载，若有可尝试执行dotnet workload repair修复

内容的提问来源于stack exchange，提问作者Jack Phillips