How to Show a Message Box on Windows 10 (PowerShell and Batch)

To show a custom message box on Windows 10, call the built-in Windows Forms MessageBox.Show method from Windows PowerShell. Run it once from a terminal or save it as a reusable .bat or .ps1 file. No administrator account is needed in your signed-in desktop session.

A message box is a modal dialog that stays open until dismissed and can block interaction with its owner. It differs from a toast notification. Microsoft's MessageBox.Show reference lists the message, caption, button, and icon arguments.

Choose how to show the message

• One-time dialog: run a short command in PowerShell.
• Run it from Command Prompt: start Windows PowerShell with powershell.exe.
• Reuse it later: save the command as a batch file or PowerShell script.

The examples use Windows PowerShell and the System.Windows.Forms assembly available on Windows. The command loads that assembly, then specifies the message, title, OK button, and information icon.

Create a reusable batch file

1. Open Notepad from the Start menu. A blank document is enough for this short script.

   

2. Paste these two lines:

   @echo off
   powershell.exe -NoProfile -Command "Add-Type -AssemblyName System.Windows.Forms; [void][System.Windows.Forms.MessageBox]::Show('Backup complete.', 'Backup status', [System.Windows.Forms.MessageBoxButtons]::OK, [System.Windows.Forms.MessageBoxIcon]::Information)"

   

3. Change Backup complete. to the text you want and Backup status to the title. Keep the single quotes around both strings. The explicit button and icon values make the dialog predictable; [void] discards the method's return value because this example only needs to display the box.

   

4. Choose File > Save As. Enter ShowMessage.bat as the file name and select All Files as the file type, then save it somewhere easy to find, such as the Desktop. If you leave the type as a text document, Notepad may save it as ShowMessage.bat.txt instead.

   

5. Open the saved ShowMessage.bat file. The message box appears; click OK to close it.

   

   

Because the batch file nests PowerShell inside a quoted command, keep the text simple and avoid double quotation marks in the message and title.

Run the command directly in PowerShell

1. Open Windows PowerShell from Start.

   

2. Paste the following command and press Enter:

   Add-Type -AssemblyName System.Windows.Forms
   [void][System.Windows.Forms.MessageBox]::Show('Backup complete.', 'Backup status', [System.Windows.Forms.MessageBoxButtons]::OK, [System.Windows.Forms.MessageBoxIcon]::Information)

   

3. Click OK when the dialog appears.

   

For a reusable PowerShell script, save the two PowerShell lines above in Notepad as ShowMessage.ps1, choosing All Files. Run a Desktop copy with & "$env:USERPROFILE\Desktop\ShowMessage.ps1". If an execution policy blocks the script, use the inline command or batch file rather than changing a device-wide policy. See Microsoft's Add-Type documentation.

Show a message from Command Prompt

In Command Prompt, paste this one-line command and press Enter. It starts Windows PowerShell and passes it the dialog code:

powershell.exe -NoProfile -Command "Add-Type -AssemblyName System.Windows.Forms; [void][System.Windows.Forms.MessageBox]::Show('Backup complete.', 'Backup status', [System.Windows.Forms.MessageBoxButtons]::OK, [System.Windows.Forms.MessageBoxIcon]::Information)"

The dialog appears over the desktop; close it with OK, then Command Prompt returns to its prompt. The -NoProfile switch starts PowerShell without loading the user's profile, as described in Microsoft's Windows PowerShell command-line reference.

Use Yes and No buttons

To ask a question, change the button and icon arguments, then check the result. The method returns a DialogResult, so your script can take a different action depending on the answer:

$answer = [System.Windows.Forms.MessageBox]::Show('Continue with cleanup?', 'Confirm action', [System.Windows.Forms.MessageBoxButtons]::YesNo, [System.Windows.Forms.MessageBoxIcon]::Question)
if ($answer -eq [System.Windows.Forms.DialogResult]::Yes) { 'Continue with cleanup' } else { 'Cancelled' }

PowerShell single-quoted strings treat most characters literally. If your message itself contains an apostrophe, double it inside the string (for example, 'Don''t close this window'). See Microsoft's PowerShell quoting rules. For a batch command, also avoid double quotes inside the message because the command is nested inside a quoted -Command argument.

If the message box does not appear

• Confirm the file ends in .bat or .ps1, not .txt.
• Run it in a signed-in desktop session; a service or noninteractive process may not show UI there.
• Use Alt+Tab if the dialog may be behind another window.
• If a saved script fails, try the inline command to isolate file-name or quoting errors.

If all you need is a reminder that should not interrupt the current task, use a Windows notification instead of this modal dialog. For a simple custom pop-up that must be acknowledged, the PowerShell method above is the shortest route.