I have a product to install on a Windows 7 64 bit machine. The msi is unsigned and when the it trys to install it is blocked saying

"This file was blocked because it does not have a valid digital signature that verifies its publisher"

I have seen this before but normally you can override the block and carry on installing but in this case there is only an OK button.

Does anyone know the option/group policy or whatever it is that needs to be turned off to allow the msi to install correctly?

2 Answers 2


Old topic, but I feel the answer by @derryl is actually not even close to correct. This is the proper way to install unsigned .msi packages.

  1. Disable UAC by opening the start menu (Or use the Windows search function depending on your OS version) and locate: "uac" and slide the slider all the way down. enter image description here

  2. Open up the start menu and type cmd.exe and right mouse click -> run as administrator.

  3. Type: bcdedit /set testsigning on

  4. Reboot your machine

This is really all there is to it. You do not need to download anything and you especially don't need to run any 3:d party libraries.

note: This opens up your computer to potentially unwanted malicious softwares. So be careful when installing unsigned packages. I know Microsoft might not be the safest platform but this surely doesn't add to the default security. So be careful!

  1. Disable User Account Control (UAC)

  2. Go to Start and type cmd in the search box;

  3. Right-click on cmd.exe (should be at the top of the list) and select Run as administrator;

  4. In the newly created command prompt box, type the following and press enter:

bcdedit /set loadoptions DDISABLE_INTEGRITY_CHECKS

Note: DDISABLE is NOT a typo!

5.Download the latest Driver Signature Enforcement Overrider (DSEO) from http://www.ngohq.com/home.php?page=Files&go=cat&dwn_cat_id=34

6.There is no need to install the app, just copy it to a safe location and run it;

7.Click next and please take your time to read the license agreement, then click 'Yes';

8.Optional: select How-to-use and click 'Next'.

9.Select Enable Test Mode and click next;

10.Now select Sign a System File and click next;

11.In the text box, type the path and name of the file (see the example included), then click on OK to sign the driver;

Note: see below if don't know what files need signing.

12.After being told that the file was signed successfully, continue signing the other files (if there are any left) and then reboot;

13.Your driver should now load successfully and you may now enable UAC!

  • Thanks. The software is not a driver but I will try it
    – StuC
    Commented Apr 14, 2011 at 14:00

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