Can't install nuget package because of "Failed to initialize the PowerShell host"

Question 1

Setting an execution policy to RemoteSigned or Unrestricted should work. It must be changed under an administrator mode via a PowerShell console. Be aware that changes will be applied according to the bit version of the PowerShell console, so 32bit or 64 bit. So if you want to install a package in Visual Studio (32 bit version) which requires a specific policy you should change settings of the policy via PowerShell (x86).

The command in PowerShell (as administrator) to set the policy to unrestricted (as noted by @Gabriel in the comments) is:

start-job { Set-ExecutionPolicy Unrestricted } -RunAs32 | wait-job | Receive-Job

Having set the policy to unrestricted, you will want to set the policy back to its original after the install is complete.

Question 2

Remember to restart Visual Studio after you've done the Set-ExecutionPolicy Unrestricted in PowerShell (x86).

If that doesn't work, try Set-ExecutionPolicy RemoteSigned in PowerShell (x86) then restart Visual Studio.

Question 3

By default the PowerShell script execution is very limited for security reasons. For use within NuGet we need to open the doors.

1. Step

Open Windows PowerShell, run as Administrator

2. Step

NuGet is using the 32 bit console, so it wont be affected by changes to the 64 bit console. Run the following script to make sure you are configuring the 32 bit console.

start-job { Set-ExecutionPolicy RemoteSigned } -RunAs32 | wait-job | Receive-Job

3. Step

Restart Visual Studio

Question 4

I have the same issue with the Manage NuGet Packages dialog, I use a work-around that may help others - running from package manager console:

If I use the command line powershell commandlet install-package, all is fine.

I am adverse to changing a security setting "just to make it work".

Question 5

No answers have worked for me.

All policies were correct but I have the error when installing a package

Failed to initialize the PowerShell host. If your PowerShell execution policy setting is set to AllSigned, open the Package Manager Console to initialize the host first.

The solution : I have uninstalled the nuget package manager plugin and reinstalled it.

Question 6

Running the Visual Studio as Administrator worked for me.

Question 7

I had this issue with my Visual Studio 2015. I uninstalled and re-installed NuGet Package Manager again. It worked for me.

Question 8

I updated the Nuget package manager and that fixed it for me.

Question 9

This started happening with 6.0.4 recently for me, I don't think this is a very good solution but here is what helped me. Close Visual Studio

Open a Windows PowerShell prompt as Administrator (very important) and run the following command:Set-ExecutionPolicy Bypass
Open Visual Studio, open your solution and use Nuget to install JSON.Net (or whatever package included it as a dependency).
Once everything is working, I recommend setting the powershell execution policy back to restricted with the following command: Set-ExecutionPolicy Restricted

Question 10

I had the same problem after upgrading to Windows 10.

This worked for me

Close Visual Studio
Run Powershell as admin
Run Set-ExecutionPolicy Unrestricted
Run Visual studio as admin
Clean the project and add the nuget package

If it still doesn't work try editing devenv.exe.config

Visual Studio 2013: C:\Users\<UserName>\AppData\Local\Microsoft\VisualStudio\12.0

Visual Studio 2015: C:\Users\<UserName>\AppData\Local\Microsoft\VisualStudio\14.0

Add the following

    <dependentAssembly>
        <assemblyIdentity name="System.Management.Automation" publicKeyToken="31bf3856ad364e35" />
        <publisherPolicy apply="no" />
    </dependentAssembly>
    <dependentAssembly>
      <assemblyIdentity name="Microsoft.PowerShell.Commands.Utility" publicKeyToken="31bf3856ad364e35" />
      <publisherPolicy apply="no" />
    </dependentAssembly>
    <dependentAssembly>
      <assemblyIdentity name="Microsoft.PowerShell.ConsoleHost" publicKeyToken="31bf3856ad364e35" />
      <publisherPolicy apply="no" />
    </dependentAssembly>
    <dependentAssembly>
      <assemblyIdentity name="Microsoft.PowerShell.Commands.Management" publicKeyToken="31bf3856ad364e35" />
      <publisherPolicy apply="no" />
    </dependentAssembly>
    <dependentAssembly>
      <assemblyIdentity name="Microsoft.PowerShell.Security" publicKeyToken="31bf3856ad364e35" />
      <publisherPolicy apply="no" />
    </dependentAssembly>
    <dependentAssembly>
      <assemblyIdentity name="Microsoft.PowerShell.Commands.Diagnostics" publicKeyToken="31bf3856ad364e35" />
      <publisherPolicy apply="no" />
    </dependentAssembly>

Question 11

If the above answers dint work for you -

Open Run - windows + R
Open registry editor - type regedit.exe
Open - HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\PowerShell
In the right pane - Modify "ExecutionPolicy" and keep its "Value Data" as blank.
Restart your visual studio, Now your Powershell can initialize properly.

Question 12

This Nuget fix worked for me:

https://github.com/NuGet/Home/issues/974#issuecomment-124774650

Question 13

By default my Windows 10 64-bit only had Powershell version 1.0 enabled. I changed the control panel/Programs/Programs and features/Turn Windows features On Off.

Make sure the Windows Powershell 2.0 engine is enabled.

Restart VS2015 in non-administrator mode and with all packages installed correctly.

Question 14

I had the same problem with vs2013 and changing execution policy did not fix it. The only working solution I found was uninstalling Nuget from VS and installing it again. Steps are here: https://stackoverflow.com/a/32619961/3853238

Question 15

Close all the visual studio instances and try again. It worked for me :)

Question 16

All I needed to do was restart Visual Studio, open the NuGet Package Manager Console, and then using the Manage NuGet Packages dialog worked.

Question 17

After trying various suggested fixes, it was finally solved by updating the NuGet Package Manager extension in Visual Studio.

This is done under Tools -> Extensions And Updates, then in the Extensions and Updates dialog Updated -> Visual Studio Gallery. A restart of Visual Studio may be required.

Question 18

Had the same problem and this solved it for me (Powershell as admin):

Set-ItemProperty -Path HKLM:\Software\Policies\Microsoft\Windows\PowerShell -Name ExecutionPolicy -Value ByPass

Question 19

If you use VS 2013 Update 5, you should manually install an update 2.8.7 for NuGet Packet Manager.

The bug report has more details.

Question 20

VS2015: Updated the NuGet and worked.

Question 21

What did the trick for me was to re-install NuGet Package Manager by using the link below:

VS 2013: https://github.com/NuGet/Home/releases/download/2.8.7/NuGet.Tools.vsix

VS 2015: https://github.com/NuGet/Home/releases/download/3.1.1/NuGet.Tools.vsix

Question 22

If none of the above helps, see if you can update Visual Studio.

I Had the same issue with Visual Studio 2017 Community when I tried to install Newtonsoft.Json. The ExecutionPolicy change didn't help (I tried using both PowerShell and Registry Editor). I also tried to uninstall and install NuGet.

After running VS2017 setup file, it asked for update of Visual Studio. All the problems disappeared after the update.

Question 23

For me setting the execution policy to Unrestricted did not work. I had to repair the vs2013 installation by going into Control Panel. Repairing the installation worked for me.

Question 24

after trying all the suggested solution nothing worked on VS 2015 update 2

deleting the package folder from the solution folder and restoring it from visual studio worked for me

Question 25

I had a similar problem. I have fixed it by turning "Windows PowerShell 2.0" feature on in "Turn Windows features on or off". Note that this feature is turned on by default, I manually turned it off few days ago.

I'm working on Windows 10 Pro 64bit and same problem was with Visual Studio 2015 and 2017 (32bit and 64bit app)

Question 26

Download and Install Administrative Templates for Windows PowerShell

Next:  Powershell x86 from As Administrator

Run:   Get-ExecutionPolicy -List  , and see if you have RemoteSigned etc..

1. 5 different scopes  Set-ExecutionPolicy "RemoteSigned" -Scope Process -Confirm:$false

2. Machine and User Policy you have to set through the Group Policy Administration Template in 2 areas.

UPDATE - EDIT:

Set ALL of them to  "Undefined" and ONLY the LocalMachine to "Restricted"

This is what fixed might after I had given my powershell more permissions not knowing that it would mess up visual studio 2013 and 2015

Question 27

This issue is not always related to the PowerShell Execution Policy. My machine is configured as "Unrestricted" for both PowerShell x64 and x86, but I still get this error message from times to times in Visual Studio 2013.

When I try to open the Package Manager Console:

Windows PowerShell updated your execution policy successfully, but the setting is overridden by a policy defined at a more specific scope. Due to the override, your shell will retain its current effective execution policy of Unrestricted. Type "Get-ExecutionPolicy -List" to view your execution policy settings. For more information please see "Get-Help Set-ExecutionPolicy".

This is not a valid error message.

Rebooting Visual Studio does not always resolve the problem.

Running the process as an admin never resolves the problem.

Like Declan, the latest update of the Package Manager plugin fixed the issue: 2.8.60723.765

Question 28

Set the execution policy to Bypass instead of Unrestricted or RemoteSigned; this tutorial gives fuller instructions. Also, if you are having trouble using PowerShell to change the policy then the author shows you how to change it in Regedit.

Question 29

There are an awful lot of stabs in the dark here, so I'll add my own.

In my case, I also got a message that there was a missing lock file, and a recommendation to run dnu restore in the package manager console. I did so, restarted VS, and everything is now working.

Question 30

What worked for me is:

Set Execution policy to Unrestricted.
Find-Module ISEModuleBrowserAddon | Install-Module
Import-Module ISEModuleBrowserAddon
Find-Module ISEScriptAnalyzerAddOn | Install-Module
Import-Module ISEScriptAnalyzerAddOn
Import-Module ScriptBrowser
In ISE, you need Enable-ScriptBrowser

And you have Module, Script, and Analyser in your ISE.

Run in Win 10 Pro, x64 Console Host 5.0.10586.122

Good Luck!