Unblock-File
Unblocks files that were downloaded from the internet.
Syntax
Unblock-File
[-Path] <String[]>
[-WhatIf]
[-Confirm]
[<CommonParameters>]
Unblock-File
-LiteralPath <String[]>
[-WhatIf]
[-Confirm]
[<CommonParameters>]
Description
This cmdlet only works on the Windows and macOS platforms.
The Unblock-File
cmdlet lets you open files that were downloaded from the internet. It unblocks
PowerShell script files that were downloaded from the internet so you can run them, even when the
PowerShell execution policy is RemoteSigned. By default, these files are blocked to protect the
computer from untrusted files.
Before using the Unblock-File
cmdlet, review the file and its source and verify that it is safe to
open.
Internally, the Unblock-File
cmdlet removes the Zone.Identifier alternate data stream, which
has a value of 3
to indicate that it was downloaded from the internet.
For more information about PowerShell execution policies, see about_Execution_Policies.
This cmdlet was introduced in Windows PowerShell 3.0.
Examples
Example 1: Unblock a file
This command unblocks the PowerShellTips.chm
file.
PS C:\> Unblock-File -Path C:\Users\User01\Documents\Downloads\PowerShellTips.chm
Example 2: Unblock multiple files
This command unblocks all of the files in the C:\Downloads
directory whose names include
"PowerShell". Do not run a command like this one until you have verified that all files are safe.
PS C:\> dir C:\Downloads\*PowerShell* | Unblock-File
Example 3: Find and unblock scripts
This command shows how to find and unblock PowerShell scripts.
The first command uses the Stream parameter of the Get-Item cmdlet get files with the Zone.Identifier stream.
The second command shows what happens when you run a blocked script in a PowerShell session in which the execution policy is RemoteSigned. The RemoteSigned policy prevents you from running scripts that are downloaded from the internet unless they are digitally signed.
The third command uses the Unblock-File
cmdlet to unblock the script so it can run in the session.
PS C:\> Get-Item * -Stream "Zone.Identifier" -ErrorAction SilentlyContinue
FileName: C:\ps-test\Start-ActivityTracker.ps1
Stream Length
------ ------
Zone.Identifier 26
PS C:\> C:\ps-test\Start-ActivityTracker.ps1
c:\ps-test\Start-ActivityTracker.ps1 : File c:\ps-test\Start-ActivityTracker.ps1 cannot
be loaded. The file c:\ps-test\Start-ActivityTracker.ps1 is not digitally signed. The script
will not execute on the system. For more information, see about_Execution_Policies.
At line:1 char:1
+ c:\ps-test\Start-ActivityTracker.ps1
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : SecurityError: (:) [], PSSecurityException
+ FullyQualifiedErrorId : UnauthorizedAccess
PS C:\> Get-Item C:\ps-test\Start-ActivityTracker.ps1 | Unblock-File
Parameters
-Confirm
Prompts you for confirmation before running the cmdlet.
Type: | SwitchParameter |
Aliases: | cf |
Position: | Named |
Default value: | False |
Required: | False |
Accept pipeline input: | False |
Accept wildcard characters: | False |
-LiteralPath
Specifies the files to unblock. Unlike Path, the value of the LiteralPath parameter is used
exactly as it is typed. No characters are interpreted as wildcards. If the path includes escape
characters, enclose it in single quotation marks ('
). Single quotation marks tell PowerShell not
to interpret any characters as escape sequences.
Type: | String[] |
Aliases: | PSPath, LP |
Position: | Named |
Default value: | None |
Required: | True |
Accept pipeline input: | True |
Accept wildcard characters: | False |
-Path
Specifies the files to unblock. Wildcard characters are supported.
Type: | String[] |
Position: | 0 |
Default value: | None |
Required: | True |
Accept pipeline input: | False |
Accept wildcard characters: | True |
-WhatIf
Shows what would happen if the cmdlet runs. The cmdlet is not run.
Type: | SwitchParameter |
Aliases: | wi |
Position: | Named |
Default value: | False |
Required: | False |
Accept pipeline input: | False |
Accept wildcard characters: | False |
Inputs
You can pipe a file path to this cmdlet.
Outputs
None
This cmdlet returns no output.
Notes
- Support for macOS was added in PowerShell 7.
- The
Unblock-File
cmdlet works only in file system drives. Unblock-File
performs the same operation as the Unblock button on the Properties dialog box in File Explorer.- If you use the
Unblock-File
cmdlet on a file that is not blocked, the command has no effect on the unblocked file and the cmdlet does not generate errors.
Related Links
PowerShell
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