我的Powershell v5.1不会使用install-module自动安装几乎任何模块，而手动安装确实有效。
首先，当我运行install-module时，它会下载模块，然后抛出一个错误，比如pscx模块：

PackageManagement\Install-Package : Package 'Pscx' failed to be installed because: Specified cast is not valid.
At C:\Program Files\WindowsPowerShell\Modules\PowerShellGet\2.0.4\PSModule.psm1:9307 char:21
+ ...          $null = PackageManagement\Install-Package @PSBoundParameters
+                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidResult: (Pscx:String) [Install-Package], Exception
    + FullyQualifiedErrorId : Package '{0}' failed to be installed because: {1},Microsoft.PowerShell.PackageManag
   ement.Cmdlets.InstallPackage

我现在能做的就是手动下载模块并自己使用import-module。几乎每次尝试通过此cmdlet安装任何模块时都会发生此错误。我如何解决这个问题？
对于故障排除，Get-PSRepository给了我这个：

PS C:\> Get-PSRepository

Name                      InstallationPolicy   SourceLocation
----                      ------------------   --------------
PSGallery                 Trusted              https://www.powershellgallery.com/api/v2
GalleryRolling            Trusted              https://www.poshtestgallery.com/api/v2/

编辑：

在尝试使用Save-Module时出现相同的错误：

PS C:\> Find-Module -Name 'pscx' | Save-Module -Path "G:\Temp\System Documents\WindowsPowerShell\Modules"
WARNING: Package 'Pscx' failed to be installed because: Specified cast is not valid.
WARNING: Package 'Pscx' failed to install.
PackageManagement\Save-Package : Unable to save the module 'Pscx'.
At C:\Program Files\WindowsPowerShell\Modules\PowerShellGet\2.0.4\PSModule.psm1:11331 char:25
+ ...             $null = PackageManagement\Save-Package @PSBoundParameters
+                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (Microsoft.Power...ets.SavePackage:SavePackage) [Save-Packag
   e], Exception
    + FullyQualifiedErrorId : ProviderFailToDownloadFile,Microsoft.PowerShell.PackageManagement.Cmdlets.Save
   Package

它下载了包，然后显示WARNING。
当单独使用Find-Module时，结果是：

PS C:\> Find-Module -Name 'pscx'

Version              Name                                Repository           Description
-------              ----                                ----------           -----------
3.3.2                Pscx                                PSGallery            PowerShell Community Extensi...

编辑2：

哦，我忘了说，有没有在特定的下载文件夹中创建的文件后，下载进程栏消失了。这是否意味着下载失败？

编辑3：@Sage Pourpre

1. Debugging log
   1.我总是以管理员的身份运行PS。
2. -Scope CurrentUser抛出相同的错误。

• PS C:\> Uninstall-Module -Name "PowerShellGet"和PS C:\> Uninstall-Script -Name "PowerShellGet" -RequiredVersion 2.0.3产生相同的结果。

PackageManagement\Uninstall-Package：未找到与指定的搜索条件和脚本名称“PowerShellGet”匹配的项。At C：\Program Files\WindowsPowerShell\Modules\PowerShellGet\2.0.4\PSModule.psm1：12343 char：21

• ... $null = PackageManagement\Uninstall-Package @PSBoundParameters

+ CategoryInfo          : ObjectNotFound: (Microsoft.Power...ninstallPackage:UninstallPackage) [Uninstal
l-Package], Exception
+ FullyQualifiedErrorId : NoMatchFound,Microsoft.PowerShell.PackageManagement.Cmdlets.UninstallPackage

然后我试着列出可用的模块：

PS C:\> Get-Module -ListAvailable

    Directory: G:\Temp\System Documents\WindowsPowerShell\Modules

ModuleType Version    Name                                ExportedCommands
---------- -------    ----                                ----------------
Binary     2.7.1.7    ISESteroids                         {Get-PSSharperData, Add-SteroidsContextMenuComma...
Script     1.2        Use-RawPipeline                     {Invoke-NativeCommand, Receive-RawPipeline, Get-...

    Directory: C:\Program Files\WindowsPowerShell\Modules

ModuleType Version    Name                                ExportedCommands
---------- -------    ----                                ----------------
Script     1.0.1      Microsoft.PowerShell.Operation.V... {Get-OperationValidation, Invoke-OperationValida...
Script     1.2.4      PackageManagement                   {Find-Package, Get-Package, Get-PackageProvider,...
Script     4.5.0      Pester                              {Describe, Context, It, Should...}
Script     2.0.4      PowerShellGet                       {Find-Command, Find-DSCResource, Find-Module, Fi...
Script     2.0.3      PowerShellGet                       {Find-Command, Find-DSCResource, Find-Module, Fi...
Script     1.2        PSReadline                          {Get-PSReadlineKeyHandler, Set-PSReadlineKeyHand...

    Directory: C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules

ModuleType Version    Name                                ExportedCommands
---------- -------    ----                                ----------------
Manifest   1.0.0.0    AppBackgroundTask                   {Disable-AppBackgroundTaskDiagnosticLog, Enable-...
Manifest   2.0.0.0    AppLocker                           {Get-AppLockerFileInformation, Get-AppLockerPoli...
Manifest   1.0.0.0    AppvClient                          {Add-AppvClientConnectionGroup, Add-AppvClientPa...
Manifest   2.0.0.0    Appx                                {Add-AppxPackage, Get-AppxPackage, Get-AppxPacka...
Script     1.0.0.0    AssignedAccess                      {Clear-AssignedAccess, Get-AssignedAccess, Set-A...
Manifest   1.0.0.0    BitLocker                           {Unlock-BitLocker, Suspend-BitLocker, Resume-Bit...
etc...

和Get-InstalledModule

PS C:\> Get-InstalledModule -Name "PowerShellGet" -RequiredVersion 2.0.3
PackageManagement\Get-Package : No match was found for the specified search criteria and module names
'PowerShellGet'.
At C:\Program Files\WindowsPowerShell\Modules\PowerShellGet\2.0.4\PSModule.psm1:9050 char:9
+         PackageManagement\Get-Package @PSBoundParameters | Microsoft. ...
+         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (Microsoft.Power...lets.GetPackage:GetPackage) [Get-Package],
   Exception
    + FullyQualifiedErrorId : NoMatchFound,Microsoft.PowerShell.PackageManagement.Cmdlets.GetPackage