What is Interop.IWshRuntimeLibrary.dll? Should I remove it?

Interop.IWshRuntimeLibrary.dll is a shared library file that rarely causes problems

Interop.IWshRuntimeLibrary.dll is a DLL file that is related to Act! 2009 by Sage Software. Act! 2009 is a contact management software that lets users bring a lot of different kinds of information together. The latest version of this file is, and it was produced for Windows Operating Systems. The average size of the of the file is about 49KB.

Name Interop.IWshRuntimeLibrary.dll
Type Dynamic link library file
Danger Level Low if not caused by malware
Associated programs Act! 2009, SDL MultiTerm, Advanced System, Activeris AntiMalware, RegServe
OS Windows 10/8/7/Vista/XP/ME/2000
Latest version

IT specialists observed that Interop.IWshRuntimeLibrary.dll could also be related to multiple other applications, such as SDL MultiTerm, Advanced System Protector, Activeris AntiMalware and RegServe. On its own, the file is not malicious and is related to computer software.

DLL stands for dynamic link library, and these files are very similar to .exe files. They are executable files; however, they cannot be launched without the .exe file. DLL allows different software to share same functionality, for example, printing. Whenever to use a program to print a document, the Interop.IWshRuntimeLibrary.dll is used to do so. If you decide to use the same function in another app, the same file will be called up again.

Software developers benefit significantly from DLL files. However, because Interop.IWshRuntimeLibrary.dll is “outside” of the program and does not directly exists within one, it can create an opportunity to cause multiple error messages.

These are the error messages you could encounter during system boot up, program startup/closedown or while trying to use a specific function:

  • Interop.IWshRuntimeLibrary.dll Missing
  • Interop.IWshRuntimeLibrary.dll Not Found
  • Cannot register Interop.IWshRuntimeLibrary.dll
  • This application failed to start because Interop.IWshRuntimeLibrary.dll was not found. Re-installing the application may fix this problem
  • Cannot find C:\Windows\System32\Interop.IWshRuntimeLibrary.dll
  • Etc

In most cases, these errors occur because of missing or corrupt Interop.IWshRuntimeLibrary.dll files. When Interop.IWshRuntimeLibrary.dll cannot be properly loaded, it will produce an error message. For example, if you shut down your PC incorrectly, you could encounter one of these messages.

If you detect multiple Interop.IWshRuntimeLibrary.dll processes running on your Task Manager, it is time to run a full computer scan using FortectIntego or other reputable security software. If you see several Interop.IWshRuntimeLibrary.dll processes running, it is quite likely that it can be caused by a computer virus which should be eliminated immediately.

In other cases, these errors can be related to corrupt Windows registry entries. These broken entries could result in moved DLL file, missing DLL file or a leftover DLL file reference in your Windows registry.

Ways you can protect yourself from malware infections

As we already mentioned, Interop.IWshRuntimeLibrary.dll errors can be caused by malware infection. To protect your computer from dangerous viruses, please follow these guidelines:

  • Never open email attachments or click on links in an email from an unknown source. The attachment is especially hazardous if it asks you to boot up Macro function to open it;
  • Stay away from file sharing, torrent, and other third-party websites. File sharing websites are known to inject installers with a malicious payload that can cause devastating consequences to your computer. Besides, downloading illegal software is a crime;
  • If you get an error message that notifies you that the file is corrupt or missing, never try to download it from third-party websites. We recommend checking other solution methods – you can find them below;
  • Do not click on suspicious ads or links;
  • Employ a robust security tool and keep it up to date;
  • Keep regular back-ups.

Fix Interop.IWshRuntimeLibrary.dll error messages

Perform full system scan for malware

As we already mentioned, the Interop.IWshRuntimeLibrary.dll error might be caused by a virus. Therefore, we highly advise running a full computer scan using FortectIntego, SpyHunter 5Combo Cleaner or Malwarebytes to determine if malware is not at fault. Do not forget that trojans can replace original DLL files.

Update your Windows OS

An outdated operating system might cause various Interop.IWshRuntimeLibrary.dll errors. Sometimes, installing Windows updates can solve the problem:

  • Select Start button and type Update in the search box
  • Tap Enter
  • Windows Update window will appear
  • Click the Install Updates button
  • Restart your PC

Update your drivers

  • Click the Start button and type Device Manager – select it from the search results
  • Expand one of the category you want to update, for example, graphics driver
  • Right-click on the selected graphics card and click Update Driver
  • Select Search automatically for updated driver software
  • Windows will automatically find and install updates
  • Restart your computer

Re-register Interop.IWshRuntimeLibrary.dll using Microsoft Register server

  • Select Start button and type Command in the search box
  • Hold Ctrl + Shift and press Enter
  • When the dialog box appears, enter the following command: regsvr32 /u Interop.IWshRuntimeLibrary.dll and hit Enter
  • Type the following text: regsvr32 /i Interop.IWshRuntimeLibrary.dll and press Enter again
  • Close down command prompt and restart the program associated with Interop.IWshRuntimeLibrary.dll file

Use System Restore

  • Select Start button and type System Restore and hit Enter
  • Select System Restore from search results
  • Follow the steps in Wizard and choose the appropriate restore point (before errors start occurring)


do it now!
Fortect Happiness
Intego Happiness
Compatible with Microsoft Windows Compatible with macOS
What to do if failed?
If you failed to fix virus damage using Fortect Intego, submit a question to our support team and provide as much details as possible.
Fortect Intego has a free limited scanner. Fortect Intego offers more through scan when you purchase its full version. When free scanner detects issues, you can fix them using free manual repairs or you can decide to purchase the full version in order to fix them automatically.
Alternative Software
Different software has a different purpose. If you didn’t succeed in fixing corrupted files with Fortect, try running SpyHunter 5.
Alternative Software
Different software has a different purpose. If you didn’t succeed in fixing corrupted files with Intego, try running Combo Cleaner.
About the author
Julie Splinters
Julie Splinters - Anti-malware specialist

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