Why is my locally-created script not allowed to run under the RemoteSigned execution policy?

Some things to check:

Can you change to unrestricted?

Set-ExecutionPolicy Unrestricted

Is the group policy set?

• Computer Configuration\Administrative Templates\Windows Components\Windows PowerShell
• User Configuration\Administrative Templates\Windows Components\Windows PowerShell

Also, how are you calling Script.ps1?

Does this allow it to run?

powershell.exe -executionpolicy bypass -file .\Script.ps1

Is the file being blocked? I had the same issue and was able to resolve it by right clicking the .PS1 file, Properties and choosing Unblock.

I finally tracked this down to .NET Code Access Security. I have some internally-developed binary modules that are stored on and executed from a network share. To get .NET 2.0/PowerShell 2.0 to load them, I had added a URL rule to the Intranet code group to trust that directory:

PS> & "$Env:SystemRoot\Microsoft.NET\Framework64\v2.0.50727\caspol.exe" -machine -listgroups
Microsoft (R) .NET Framework CasPol 2.0.50727.5420
Copyright (c) Microsoft Corporation.  All rights reserved.

Security is ON
Execution checking is ON
Policy change prompt is ON

Level = Machine

Code Groups:

1.  All code: Nothing
    1.1.  Zone - MyComputer: FullTrust
        1.1.1.  StrongName - ...: FullTrust
        1.1.2.  StrongName - ...: FullTrust
    1.2.  Zone - Intranet: LocalIntranet
        1.2.1.  All code: Same site Web
        1.2.2.  All code: Same directory FileIO - 'Read, PathDiscovery'
        1.2.3.  Url - file://Server/Share/Directory/WindowsPowerShell/Modules/*: FullTrust
    1.3.  Zone - Internet: Internet
        1.3.1.  All code: Same site Web
    1.4.  Zone - Untrusted: Nothing
    1.5.  Zone - Trusted: Internet
        1.5.1.  All code: Same site Web

Note that, depending on which versions of .NET are installed and whether it's 32- or 64-bit Windows, caspol.exe can exist in the following locations, each with their own security configuration (security.config):

• $Env:SystemRoot\Microsoft.NET\Framework\v2.0.50727\
• $Env:SystemRoot\Microsoft.NET\Framework64\v2.0.50727\
• $Env:SystemRoot\Microsoft.NET\Framework\v4.0.30319\
• $Env:SystemRoot\Microsoft.NET\Framework64\v4.0.30319\

After deleting group 1.2.3....

PS> & "$Env:SystemRoot\Microsoft.NET\Framework64\v2.0.50727\caspol.exe" -machine -remgroup 1.2.3.
Microsoft (R) .NET Framework CasPol 2.0.50727.9136
Copyright (c) Microsoft Corporation.  All rights reserved.

The operation you are performing will alter security policy.
Are you sure you want to perform this operation? (yes/no)
yes
Removed code group from the Machine level.
Success

...I am left with the default CAS configuration and local scripts now work again. It's been a while since I've tinkered with CAS, and I'm not sure why my rule would seem to interfere with those granting FullTrust to MyComputer, but since CAS is deprecated as of .NET 4.0 (on which PowerShell 3.0 is based), I guess it's a moot point now.