There are times when you try to open a file, an executable file for instance, but were unable to do so since you encounter an error in an Open File – Security Warning dialog box that says, “This publisher has been blocked from running software on your machine, You must unblock this publisher to run this software”. This kind of error is most likely thrown by your operating system because it considers the file to be unsafe and could potentially harm your computer. However, if you’re certain that the file is harmless, read on as this post will walk you through in fixing the error so you can open the file without getting an error.

There are various options you can check out to fix the error. You may run the program using Command Prompt or unblock it using File Properties. You could also try turning off SmartScreen or use the unblock file command in Windows PowerShell.

Option 1 – Try running the program via Command Prompt

  • Tap the Win + R keys to open the Run dialog box and type “cmd” in the field and hit Enter to open Command Prompt.
  • Next, tap the Shift key and right click on the program or the executable file and then select the “Copy as path” option.
  • After that, paste this path in the Command Prompt window and tap Enter to open the program.

Option 2 – Try to unblock the file using File Properties

  • Right click on the file you were trying to open and select Properties.
  • Next, click the Unblock button and then click on the Apply and OK buttons.

  • You should now be able to open or access the file without getting the error.

Option 3 – Turn off SmartScreen

The next thing you can do is to turn off SmartScreen temporarily. All you have to do is open the Windows Defender Security Center and from there, go to the App & browser control section. After that, click on the radio button for Off under Check apps and files. Once you’re done, try opening the file again. Don’t forget to enable the SmartScreen back on.

Option 4 – Try to use the Unblock-File command in PowerShell

You might also want to utilize the Unblock-File command in Windows PowerShell as it will unblock the file so you can open it. To execute this command, follow these steps:

  • Tap the Win + X keys and then click on Windows PowerShell.
  • After opening PowerShell, type or copy and paste this command and tap Enter to execute it: Get-ChildItem -Path ‘C:\Users\<username>\Downloads\’ | Unblock-File
  • The command you entered will unblock all the files in the Downloads folder, assuming that’s where the file you were trying to open is stored. If it’s not, then replace path with the path where the file is located. Take note to also replace “<username>” with your Username.
  • Now check if the file has been unblocked by accessing or opening it.

On top of the “This publisher has been blocked from running software on your machine” error when opening a file in Windows 10, if you are also facing other issues right now which has been bothering you for quite some time, there is a one-click solution known as Advanced System Repair you can use. This program is a useful tool that could repair corrupted registries and optimize your PC’s overall performance. Aside from that, it also cleans out your computer for any junk or corrupted files that help you eliminate any unwanted files from your system. This is basically a solution that’s within your grasp with just a click. It’s easy to use as it is user-friendly. For complete set of instructions in downloading and using it, refer to the steps below.

Perform a full system scan using ASR. To do so, follow these steps:

  1. Turn on your computer. If it’s already on, you have to reboot

  1. After that, the BIOS screen will be displayed, but if Windows pops up instead, reboot your computer and try again. Once you’re on the BIOS screen, repeat pressing F8, by doing so the Advanced Option shows up.
  1. To navigate the Advanced Option use the arrow keys and select Safe Mode with Networking then hit
  1. Windows will now load the Safe Mode with Networking.
  1. Press and hold both R key and Windows key.

  1. If done correctly, the Windows Run Box will show up.
  1. Type in the URL address in the Run dialog box and then tap Enter or click OK.
  1. After that, it will download the program. Wait for the download to finish and then open the launcher to install the program.
  1. Once the installation process is completed, run ASR to perform a full system scan.

  1. After the scan is completed click the “Fix, Clean & Optimize Now” button.