If you are seeing an error code 0x800F081F when you try to install .NET Framework 3.5 on your Windows computer, you are not alone. Many Windows users are reporting it. But the good news is you can fix this error. Here are two fixes you can try:
The 0x800F081F error may occur because the component setting in Group Policy is disabled. You should enable it to see if this fixes the error. To do so:
1) On your keyboard, press the Windows logo key and R key at the same time to invoke the Run box.
2) Type “gpedit.msc” and press Enter on your keyboard.
3) Go to Computer Configuration -> Administrative Templates -> System.
4) Double click Specify settings for optional component installation and component repair.
5) Select Enabled. Then click OK.
6) Try installing .NET Framework 3.5. If this method works for you, you won’t see the error again. Otherwise, you should try the method below.
It is also possible that the error occurs because the .NET Framework 3.5 feature has not been enabled in your system. You can use a DISM command to enable it.
NOTE: You need to have installation media or an ISO image for your Windows version to perform this method.
To enable the .NET Framework 3.5 feature using DISM:
1) Put the Windows installation media into your computer, or mount the Windows ISO image in your system.
2) Press the Windows logo key on your keyboard. Then type “cmd“.
3) Right-click “Command Prompt” and select “Run as administrator“.
4) Type “Dism /online /enable-feature /featurename:NetFx3 /All /Source:<DRIVE>:\sources\sxs /LimitAccess” and press Enter on your keyboard. (Note that you need to replace the <DRIVE> here with the drive letter for the installation media drive or the ISO drive.)
5) Try installing .NET Framework 3.5 and see if the error disappears.