Fix Osetup.dll Digital Signature Error

Osetup.dll (Office Setup Engine) is an essential part of the Microsoft Office suite. By default, the osetup.dll file is located in a subfolder of c:\program files.

In this article, we will discuss a common osetup.dll error that you may encounter while installing Office 2007 or any of its individual products, such as Outlook 2007.

We will also discuss the tasks you can perform to minimize the occurrence of DLL errors.

Osetup.dll error

When installing Office 2007, you may receive the following error:

“X:\outlookr.WW\Osetup.DLL digital signature does not validate or is not present.”

Note: X is a variable and refers to your CD/DVD drive.


To resolve the above error, you can use either of the methods discussed in detail below.

Method 1 – Manually Start the Installation

  1. Click Start and then click Run.
  2. Next, click the Browse button and navigate to your CD or DVD drive.
  3. Double-click setup.exe.

Method 2 – Copy the Installation Files to a Network Share

If the computer on which you wish to install Office 2007 is on a network, copy the whole installation directory into a shared folder on the network. Next, on the target computer (PC on which you want to install Office 2007) open the Run box, browse to the network share where you have copied the contents of the CD and double-click the setup.exe.

Method 3 – Copy the Installation Files to your computer’s hard disk

Copy the contents of the Office 2007 CD on your hard disk and replace the non-working osetup.dll file with the osetup.dll file from another Office software on your CD.

How to prevent DLL errors

By regularly performing the three simple tasks you can prevent various DLL errors from occurring:

Run regular malware scans – Malware infection is perhaps the biggest cause of DLL errors. Safeguard your PC from malware programs by installing robust antivirus and antispyware tools. Further, regularly update your protective software with the latest malware definitions and security updates to ensure that your protective tool identifies and protects your computer from the latest malware.

Install new Windows updates – Microsoft regularly releases new updates, hotfixes and security patches that are aimed to boost your system security and fix any known Windows errors. Regularly install new updates that are released for your version of Windows.

Clean your registry – A corrupt or bloated registry may cause various errors, including recurring DLL errors. To prevent errors from occurring due to registry issues, regularly clean your registry using advanced registry cleaning software, such as RegServe.

“Can osetup.dll digital signature does not validate error” be fixed by downloading the DLL from the Internet?

As the above error occurs due to a problem with the digital signature of the osetup.dll file, the issue is not likely to be resolved by downloading a copy of the osetup.dll file from an online DLL directory.