The .NET Framework 3.5 error code 0x800f081f occurs when the system is unable to find the required files for installation. This could happen if the files are missing from the source, or if the download was incomplete. It is also possible that the error is caused by a corrupted file.
1. Restart your computer and then try installing the .NET Framework 3.5 again
- Open the Start menu and select Settings.
- Under System and Security, click Restart.
- Click on the "Troubleshoot" button.
- Under "Advanced options," select "Startup Settings."
- Under "Restart," click on the "Restart now" button.
- When your computer restarted, select "Install the update" from the screen that pops up.
- Select "Windows 10 Enterprise."
- Click on the "Next" button.
- Select "Install now."
- Confirm the installation by clicking on the "Finish" button.
2. Use the DISM tool to fix corruptions in the Windows component store
- In the DISM tool, select the local or remote machine that you want to fix.
- On the left side of the DISM tool window, select the “Component Store” option.
- On the right side of the Component Store window, select the “ corruptions ” tab.
- In the “Corruptions” tab, select the corruption that you want to fix.
- In the “Fix options” window, select the action that you want to take.
- In the “Fix options” window, select the restore point that you want to use.
- In the “Browse” window, select the media that you want to use to restore the corruption.
- In the “Start repairing” window, wait until the corruption is fixed.
3. Use the System File Checker tool to repair missing or corrupted system files
- Click on the Start button, type “cmd” in the search box, and press ENTER.
- Type “systemfilechecker” and press ENTER.
- The System File Checker tool will start and display the results.
- Review the results and take appropriate action, such as repairing missing or corrupted system files.
4. Register the required DLL files for the .NET Framework 3.5
- Go to the folder where the .NET Framework 3.5 files are located.
- Copy the following files to the folder:
- Restart your computer.
- When the computer starts, it will search for the new files and install them.
Some users might also have success with the following opitons:
- Try installing the .NET Framework 3.5 from a network share or from a local copy.
- Reinstall the .NET Framework 3.5 using the offline installer.
- Install the .NET Framework 3.5 on a different computer and then copy it over to your computer.
- Use the Group Policy Editor to enable the .NET Framework 3.5.