Troubleshoot for a hardware problem if any urlmon.dll errors persist. Make sure you've made the best attempt possible to fix the urlmon.dll error using a troubleshooting step prior to this one. Important: All the information on your hard drive will be erased during a clean install. If none of the steps above correct the urlmon.dll error, this should be your next course of action.
A clean install of Windows will erase everything from the hard drive and install a fresh copy of Windows.
I've included the option here as a "last resort" attempt before the destructive step coming up next. Important: I rarely recommend the use of registry cleaners. A free registry cleaner program may be able to help by removing invalid urlmon.dll registry entries that might be causing the DLL error. Use a free registry cleaner to repair urlmon.dll related issues in the registry. If the individual urlmon.dll file troubleshooting advice above is unsuccessful, performing a startup repair or repair installation should restore all Windows DLL files to their working versions. If the hardware fails any of your tests, replace the memory or replace the hard drive as soon as possible. I've left the majority of hardware troubleshooting to the last step, but your computer's memory and hard drive are easy to test and are the most likely components that might cause urlmon.dll errors as they fail. Test your memory and then test your hard drive. The urlmon.dll file could be included in one of those updates.
Many service packs and other patches replace or update some of the hundreds of Microsoft distributed DLL files on your computer. If this DLL file is provided my Microsoft, the System File Checker tool should restore it. Run the sfc /scannow System File Checker command to replace a missing or corrupt copy of the urlmon.dll file. Roll back a driver to a previously installed version if urlmon.dll errors began after updating a particular hardware device's driver. The key here is to pay very close attention to the context of the error and troubleshoot accordingly. Note: The urlmon.dll file may or may not be related to video cards - this was just an example.
If, for example, you're receiving a "The file urlmon.dll is missing" error when you play a 3D video game, try updating the drivers for your video card. Update the drivers for hardware devices that might be related to urlmon.dll. Reinstalling the program that provides the urlmon.dll file, if possible, is a likely solution to this DLL error. Important: Try your best to complete this step. If the urlmon.dll DLL error occurs when you use a particular program, reinstalling the program should replace the file. Reinstall the program that uses the urlmon.dll file. If you suspect that the urlmon.dll error was caused by a change made to an important file or configuration, a System Restore could solve the problem. Use System Restore to undo recent system changes. It's even possible that the urlmon.dll error you're seeing is related to a hostile program that's masquerading as the file. Some urlmon.dll errors could be related to a virus or other malware infection on your computer that has damaged the DLL file. Run a virus/malware scan of your entire system. Important: Recovering a deleted copy of urlmon.dll with a file recovery program is a smart idea only if you're confident you've deleted the file yourself and that it was working properly before you did that. If you suspect that you've accidentally deleted urlmon.dll but you've already emptied the Recycle Bin, you may be able to recover urlmon.dll with a free file recovery program. The easiest possible cause of a "missing" urlmon.dll file is that you've mistakenly deleted it. Note: Start Windows in Safe Mode to complete any of the following steps if you're unable to access Windows normally due to the urlmon.dll error. If you need a copy of urlmon.dll, it's best to obtain it from its original, legitimate source.
There are many reasons why downloading a DLL file is a bad idea.
Important: Do not download urlmon.dll from a "DLL download" website.