Fix: Dcomp.dll is Missing, Not Authorized to Run, or Faulting Mode

The dcomp.dll file, developed by Microsoft and a part of the DirectComposition API, has been included in the OS since Windows 8 and can be found on Windows 11. But when the DLL is corrupt or missing, programs that rely on it start to crash, including Office apps like Microsoft Excel and several games.

Also, in some cases, the error message reads, C:\Windows\System32\dcomp.dll is either not designed to run on Windows or it contains an error. Try installing the program again using the original installation media or contact your system administrator or the software vendor for support.

Before you proceed, reboot the PC and install any pending Windows. For most of you, this should fix the dcomp.dll missing error!

How can I fix the dcomp.dll error?

Tip

Although several websites claim to host dcomp.dll, I recommend against downloading the DLL from any third-party sources. It’s because such files often come bundled with malware that can harm your PC.

1. Manually move dcomp.dll

When dcomp.dll is not designed to run on Windows or is missing, your primary approach should be to manually move a fresh copy of the DLL. The dcomp.dll file is stored in: C:\Windows\System32

So, all you have to do is go to another PC running the same Windows iteration and architecture (32-bit or 64-bit) > locate the DLL > transfer a copy of it to a USB flash drive > connect the flash drive to the affected PC > move dcomp.dll to the System32 folder > reboot the PC.

Once done, programs should no longer throw the missing DLL error!

2. Run the program as an administrator

1. Right-click on the affected program’s launcher (.exe) file, and select Properties.
2. Navigate to the Compatibility tab, and tick the checkbox for Run this program as an administrator.
3. Click on Apply and OK to save the changes.
4. Relaunch the app and check for improvements.

Running as an administrator especially helps when Microsoft Office apps like Excel, Word, or Outlook keep crashing or restarting due to dcomp.dll.

In that case, search for the affected application > right-click on the result > select Open File Location > right-click on the shortcut > select Properties > go to the Shortcut tab > click on Advanced > tick the checkbox for Run as administrator > save the changes.

3. Repair the corrupted system files

1. Press Windows + R to open Run, type cmd, and hit Ctrl + Shift + Enter.
2. Click Yes in the UAC prompt.
3. Paste the following commands individually and hit Enter after each: DISM /Online /Cleanup-Image /CheckHealth DISM /Online /Cleanup-Image /ScanHealth DISM /Online /Cleanup-Image /RestoreHealth
4. Next, run this SFC scan using this command: sfc /scannow
5. Finally, restart the PC to apply the changes.

Corrupted system files are just as likely to cause missing DLL errors. And since dcomp.dll is a protected system file, running the DISM (Deployment Image Servicing and Management) and SFC (System File Checker) scans will replace it with a cached copy stored on the PC.

4. Perform a malware scan

1. Press Windows + S to open Search, type Windows Security in the text field, and click on the relevant result.
2. Click on Virus & threat protection.
3. Click on Scan options.
4. Select the Full scan entry and click on Scan now.
5. Wait for the malware scan to complete. It typically takes 15-30 minutes.

5. Reinstall the affected app

1. Press Windows + R to open Run, type appwiz.cpl in the text field, and hit Enter.
2. Select the affected application from the list, and click on Uninstall.
3. Follow the on-screen instructions to complete the process and then restart the PC.
4. Now, reinstall the app from an official source and verify whether this restores the missing dcomp.dll.

6. Perform an in-place upgrade

NOTE

The steps listed here are for Windows 11. In case you are running the previous iteration of the OS, learn how to perform an in-place upgrade on Windows 10.

1. Go to Microsoft’s official website, select the OS edition and language, and download the Windows 11 ISO.
2. Run the ISO file and click Open in the confirmation prompt.
3. Run the setup.exe file.
4. Click Yes in the UAC prompt.
5. Click Next to proceed.
6. Review Microsoft’s license terms and click on Accept.
7. Make sure the setup reads, Keep personal files and apps, click Install, and confirm the change.
8. Wait for the in-place upgrade to complete. It may take 30-90 minutes.

An in-place upgrade will, in all likelihood, fix the missing dcomp.dll error in Windows 11 without affecting the files and apps. If this, too, fails, you can always reinstall Windows to get things running.

Before you leave, discover expert tips to fix all missing DLLs and resolve such issues with ease! Also, don’t miss our newest guide to learn what is hvsigpext.dll.

For any queries or to share more fixes with our readers, drop a comment below.