How to fix the ”mfc100u.dll is missing” error on Windows 10

By: Aleksandar Ognjanovic
5 minute read
mfc100u.dll is missing

For various PC problems, we recommend this tool.

This software will repair common computer errors, protect you from file loss, malware, hardware failure and optimize your PC for maximum performance. Fix PC issues now in 3 easy steps:

  1. Download this PC Repair Tool rated "Excellent" on TrustPilot.com.
  2. Click “Start Scan” to find Windows issues that could be causing PC problems.
  3. Click “Repair All” to fix all issues with Patended Technologies (requires upgrade).

Missing Visual C++ DLL files can pose a serious issue, especially for vivid gamers that need redistributables in order to run most of the games. The one problem that’s quite frequently reported in Windows 10 introduces an error prompt which informs a user that the mfc100u.dll file is missing.

As you might know, DLL files are important secondary files that enable a certain application to work on the Windows platform. The special emphasis goes to DirectX and Virtual C++ runtime and their DLL files placed in the System32 folder. If only single one is missing, you won’t be able to run the program at hand and the system will prompt you with an error.

Luckily, we prepared more than a few solutions that should help you resolve this issue. If you’re stuck with a missing DLL file, make sure to check them out below.

How to address ”mfc100u.dll is missing” error in Windows 10

  1. Install Microsoft Visual C++ runtime
  2. Add all the Redistributables available
  3. Install the latest Windows updates
  4. Reinstall the problematic program
  5. Scan your system for malware

Solution 1 – Install Microsoft Visual C++ runtime

In the 95% of situations, this error occurs due to lack or incompatibility of Microsoft Visual C++ Runtime tool. This is an important Windows asset provided by Microsoft and, similarly to DirectX, it’s paramount for multimedia and gaming usability in the Windows shell. Especially gaming.

Most of the users who encountered this error tried to start the game of some kind and that was all she wrote as the error prompt suddenly appeared. So, the next obvious step is to install the proper Microsoft Visual C++ version on your system. Most of the game installations offer secondary files that need to be installed in order to play the game. And, within those files, you should be able to locate the Visual C++ installation.mfc100u.dll is missing

However, if that’s not the case, you can always download it here. Pay good attention to system architecture. Once you install Visual C++, restart your PC and the problem should be resolved. On a side note, don’t download DLL files from suspicious websites and place them manually in your System32 folder. This can take you in a world of pain, full of malware and system recoveries.

Solution 2 – Add all available redistributables

Now, even though users aren’t forced to use all iterations of Visual C++, it will cost you nothing to install all available versions. If one version, say Visual C++ 2015, supports one application or a game for that matter, that doesn’t mean that other, older games will work just as fine. They may as well prompt you with the above-mentioned DLL error and you’ll get stuck in the never ending cycle.

So, for that purpose, navigate to the official support site and download all Visual C++ iterations. Make sure to install as many redistributables as you can and restart your PC. Once you’ve dealt with it, the programs should start without the error reappearing every time.

If you’re not sure how to do it, follow the steps below:

  1. Click on this link to obtain installation files.
  2. Select the preferred Visual C++, with emphasis on proper architecture and language.
  3. Download and install various versions and restart your PC.mfc100u.dll is missing
  4. Try to start the troubled program again.

Solution 3 – Update Windows

Once you install a certain feature that’s vital for Windows 10 performance in various categories, you can expect updates to come via Windows Update. Most of the time, those are security, cumulative updates of Visual C++, but, nonetheless, they can serve you well in this matter, too.

As you’re well aware, Windows 10 updates are mandatory and automatically provided within inactive hours. But, since we’re having a problem here, you might speed up the procedure and check for updates manually.


For various PC problems, we recommend this tool.

This software will repair common computer errors, protect you from file loss, malware, hardware failure and optimize your PC for maximum performance. Fix PC issues now in 3 easy steps:

  1. Download this PC Repair Tool rated "Excellent" on TrustPilot.com.
  2. Click “Start Scan” to find Windows issues that could be causing PC problems.
  3. Click “Repair All” to fix all issues with Patended Technologies (requires upgrade).

In order to do so, follow the steps we provided below:

  1. Press Windows key + I to summon the Settings app.
  2. Choose Updates & security.
  3. Click on the ”Check for updates” button.mfc100u.dll is missing
  4. Install updates and restart your PC.

Solution 4 – Reinstall the problematic program

Still, on some rare occasions, the Visual C++ installation or reinstallation won’t suffice. Namely, the program installation might be culpable for the error at hand. Related files stored in the installation folder can get corrupted or incomplete, which will, consequently, result in errors. In order to address this matter, you’ll need to either repair or reinstall the program.

Since the majority of affected programs are actually games, you can repair them easily, either by navigating to Control Panel or by using desktop client tools that come with Steam, Batttle.net and etc. With these tools, you’ll be able to scan for installation integrity and repair the installation if needed.

However, if you’re running a game without clients, you should follow the instructions below in order to repair the troubled program or game:

  1. Type Control in the Windows Search bar and open Control Panel.
  2. In the Category view, choose to Uninstall a program.Fix''D3dx9_42.dll is missing'' in Windows 10 (2)
  3. Right-click the troubled program or game and choose Repair.
  4. Follow the further instructions and, after it’s done, restart your PC.

After that, in combination with previous solutions, you should be relieved of the ”mfc100u.dll is missing” error in Windows 10.

Solution 5 – Scan system for malware

Finally, this last solution isn’t a solution per se. This is more of a precaution measure you should take in case you’re missing DLL files, including mfc100u.dll. Namely, malware infections are mostly the reason for the sudden disappearance of DLL files. Yes, there’s a chance you’ve deleted some of them on your own, but those are isolated cases and virus threat is a problem reported on a daily basis.

What you’ll need to do is to perform a deep scan and check for malware presence on your PC. You can use third-party antimalware solutions or Windows Defender – it’s your choice. If you’re inclined towards the Windows native application, follow the steps below to perform a deep scan and resolve the issue:

  1. Open Windows Defender from the taskbar notification area.
  2. Choose Virus & threat protection.
  3. Click on the ”Run a new advanced scan” option.d3dx9_43.dll is missing
  4. Choose Windows Defender Offline Scan and click on the ”Scan now” button.

That should do it. In case you have further issues, questions, suggestions or remarks, don’t forget to share them in the comments below. We’ll look forward to hearing from you.

RELATED STORIES YOU SHOULD CHECK OUT:

For various PC problems, we recommend this tool.

This software will repair common computer errors, protect you from file loss, malware, hardware failure and optimize your PC for maximum performance. Fix PC issues now in 3 easy steps:

  1. Download this PC Repair Tool rated "Excellent" on TrustPilot.com.
  2. Click “Start Scan” to find Windows issues that could be causing PC problems.
  3. Click “Repair All” to fix all issues with Patended Technologies (requires upgrade).

Next up

Best Windows 10 antivirus software to use in 2018

By: Radu Tyrsina
7 minute read

Update – 2018 will soon come to an end and we already have a guide on what is the best antivirus you should get in […]

Continue Reading

These features are out for good with Windows 10 version 1809

iamsovy@gmail.com' By: Sovan Mandal
2 minute read

Microsoft is all set to launch its next big update, Windows 10 version 1809 in October. While that should be a nice piece of news […]

Continue Reading

Windows 10 18H2 builds no longer receive new features

By: Matthew Adams
3 minute read

The Windows 10 October 2018 Update (otherwise 18H2) rollout might now be two to three weeks away. For the last few months, new build previews […]

Continue Reading

Discussions