Software & Apps Windows How to Fix Xpcom_core.dll Not Found or Missing Errors A troubleshooting guide for xpcom_core.dll errors by Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated on May 21, 2020 Windows The Ultimate Laptop Buying Guide Tweet Share Email Xpcom_core.dll errors are caused by situations that lead to the removal or corruption of the xpcom_core DLL file. In some cases, xpcom_core.dll errors could indicate a registry problem, a virus or malware issue, or even a hardware failure. The xpcom_core.dll error message could apply to any program or system that might utilize the file on any of Microsoft's operating systems, including Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, and Windows 2000. Xpcom_core.dll Errors There are several different ways that xpcom_core.dll errors can show up on your computer. Here are some of the more common ways that you might see xpcom_core.dll errors: Xpcom_core.dll Not FoundThis application failed to start because xpcom_core.dll was not found. Re-installing the application may fix this problemCannot find [PATH]\xpcom_core.dllThe file xpcom_core.dll is missingCannot start [APPLICATION]. A required component is missing: xpcom_core.dll. Please install [APPLICATION] again Xpcom_core.dll error messages might appear while using or installing certain programs, when Windows starts or shuts down, or maybe even during a Windows installation. The context of the xpcom_core.dll error is an important piece of information that will be helpful while solving the problem. How to Fix Xpcom_core.dll Errors Do not download xpcom_core.dll from a DLL download website. There are many reasons why downloading a DLL file is a bad idea. If you need a copy of xpcom_core.dll, it's best to obtain it from its original, legitimate source. Start Windows in Safe Mode to complete any of the following steps if you're unable to access Windows normally due to the xpcom_core.dll error. Restore xpcom_core.dll from the Recycle Bin. The easiest possible cause of a "missing" xpcom_core.dll file is that you've mistakenly deleted it. If you suspect that you've accidentally deleted xpcom_core.dll but you've already emptied the Recycle Bin, you may be able to recover xpcom_core.dll with a free file recovery program. Recovering a deleted copy of xpcom_core.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. Run a virus/malware scan of your entire system. Some xpcom_core.dll errors could be related to a virus or other malware infection on your computer that has damaged the DLL file. It's even possible that the xpcom_core.dll error you're seeing is related to a hostile program that's masquerading as the file. Use System Restore to undo recent system changes. If you suspect that the xpcom_core.dll error was caused by a change made to an important file or configuration, a System Restore could solve the problem. Reinstall the program that uses the xpcom_core.dll file. If the xpcom_core.dll DLL error occurs when you use a particular program, reinstalling the program should replace the file. To completely delete the program, including every related folder and file, use a program uninstaller tool. In some cases with xpcom_core.dll errors, you have to reinstall the program in an entirely new folder, which you can do by deleting the original with one of those tools, or by renaming the original and then reinstalling into a fresh folder. Try your best to complete this step. Reinstalling the program that provides the xpcom_core.dll file, if possible, is a likely solution to this DLL error. Update the drivers for hardware devices that might be related to xpcom_core.dll. If, for example, you're receiving a "The file xpcom_core.dll is missing" error when you play a 3D video game, try updating the drivers for your video card. The xpcom_core.dll file may or may not be related to video cards—this was just an example. The key here is to pay very close attention to the context of the error and troubleshoot accordingly. Roll back a driver to a previously installed version if xpcom_core.dll errors began after updating a particular hardware device's driver. Install any available Windows updates. Many service packs and other patches replace or update some of the hundreds of Microsoft distributed DLL files on your computer. The xpcom_core.dll file could be included in one of those updates. However, even if xpcom_core.dll isn't supplied by a Windows update, the DLL file might rely on another file that does come through Windows Update. So it's always best to install all updates just in case. Test your memory and then test your hard drive. 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 xpcom_core.dll errors as they fail. If the hardware fails any of your tests, replace the memory or replace the hard drive as soon as possible. Repair your installation of Windows. If the individual xpcom_core.dll file troubleshooting advice above is unsuccessful, performing a startup repair or repair installation should restore all Windows DLL files to their working versions. Use a free registry cleaner to repair xpcom_core.dll related issues in the registry. A free registry cleaner program may be able to help by removing invalid xpcom_core.dll registry entries that might be causing the DLL error. We rarely recommend the use of registry cleaners (see why in our Registry Cleaner FAQ). They're included here as a "last resort" attempt before the destructive step coming up next. Perform a clean installation of Windows. A clean install of Windows will erase everything from the hard drive and install a fresh copy of Windows. If none of the steps above correct the xpcom_core.dll error, this should be your next course of action. All the information on your hard drive will be erased during a clean install. Make sure you've made the best attempt possible to fix the xpcom_core.dll error using a troubleshooting step prior to this one. Troubleshoot for a hardware problem if any xpcom_core.dll errors persist. After a clean install of Windows, your DLL problem can only be hardware related. Need More Help? If you're not interested in fixing this problem yourself, see How Do I Get My Computer Fixed? for a full list of your support options, plus help with everything along the way like figuring out repair costs, getting your files off, choosing a repair service, and a whole lot more.