Windows10 cannot open .NET Framework3.5 error code: 0x80072F8F
Although .NET Framework4.8 is available now, some applications may still use .NET Framework3.5. So we need to install. NET Framework3.5. To enable the windows function to open .NET Framework3.5, an error is reported. When the windows function is enabled. NET Framework3.5, windows cannot complete the requested change error code: 0x80072F8F. This is really nerve-wracking, the most annoying mistake. The author searched hard for two days and found a solution and recorded it here, hoping to help everyone.
Exploration 1 (trying to install offline):
The problem this time is obviously that Windows tried to install .NET Framework3.5 online and failed.
Since I can't follow the instructions online, try offline installation, so I went to Microsoft's official website to find the .NET Framework 3.5 offline installation package. But unfortunately, the offline installation package of .NET Framework3.5 does not support windows10. .NET Framework3.5 offline installation package address
Exploration 2 (seek help from Microsoft engineers):
Later, I communicated with Microsoft engineers, and the engineers suggested overwriting the installation system to fix this installation problem. (Special attention: This method did not solve the author's problem after I
tried it, but some friends on the Internet said that this method solved their problem successfully. Here I recommend that you try this method of overwriting the installation system if there is no way to solve it. After all, overwriting the system installation takes a long, long time, and there are certain risks.) If you overwrite the installation system, you must first download the windows10 installation medium. 10 (Professional or Home Edition system selects Windows 10, Home Chinese Edition selects Windows 10 Home Chinese Edition), and then selects the ISO file as the next step to save the found path, waiting
for creation . After the download is complete, you need to find the downloaded ISO file and right-click to open it as a file explorer. After opening, you will see several folders. Run the setup program and select "Change the Windows Installer" - "Not Now" - "Next" - "Next", and you will be prompted to save the file and apply it. After that, a system replacement repair will be done. (Special attention must be selected to keep my apps and files if you want to keep apps and files. Otherwise, you will lose everything. It is recommended to back up important data in advance.)
Exploration 3 (method of sharing on a post)
Many people say that this method is successful, but the author's attempt did not solve the author's problem (I don't know what my situation is, I am tired), since many people have solved it successfully, so I will share it with you here.
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Open the registry: cmd+r, enter regedit, and confirm;
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Find the path HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU, where the default value of UseWUServer is 1 and changed to 0;
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Open the service list (right click on this computer->management->services and applications->service), restart the Windows Update service; (Of course, if you find it troublesome to find the service, you can directly restart the computer. The service will also restart)
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At this time, you can install .net framework3.5 through windows update normally in the function;
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Restore the modification in step 2 and restart the Windows Update service
Exploration 4 (really solved the author's problem)
Enabling the .NET Framework is better handled by the Deployment Image Servicing and Management tool (aka DISM tool). If you have a Windows 10 ISO file for installing the operating system, you can use it to enable .NET Framework in seconds.
Here's the how-to section:
How to enable .NET Framework 3.5 on Windows 10
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Create a temporary folder at the system root (i.e., if Windows is installed on the C: drive, create the Temp folder so it can be located at C:\Temp).
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Find the Windows 10 ISO file in File Explorer, right-click it and select Mount. Restart your computer and you'll find the ISO file mounted to the DVD drive with a temporary drive letter. (You can also plug in a Windows 10 installation bootable USB).
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Open this drive and open the "sources" folder. Now copy the sxs folder to the temporary folder created in step 1.
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Now open Powershell in windows right click on it and select run as administrator.
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Finally, in Windows PowerShell (must be run as administrator), type the following command and press Enter:
dism.exe /online /enable-feature /featurename:NetFX3 /All /Source:c:\temp\sxs /LimitAccess
- After a few seconds you will receive an "Operation completed successfully" message indicating that .NET Framework has been enabled on your system.
Finish
.NET Framework3.5 successfully started! ! !
Troubleshooting
If the following error occurs after typing the command in the last step of the above process:
C：\Windows\system32>Dism /online /enable-feature /featurename：NetFx3 /source：E：\sources\sxs /all /LimitAccess
部署映像服务和管理工具
版本： 10.0.10240.16384
映像版本： 10.0.10240.16384
启用功能
[=====================================================================================================================================================================================================
发生错误 – Microsoft-Windows-NetFx3-OnDemand-Package 错误：0x800736b3
错误： 14003
系统上未安装引用的程序集。
DISM 日志文件可在 C：\Windows\Logs\DISM\dism.log中找到
C：\Windows\system32>_
Fix: Referenced assemblies not installed on Windows 10 systems
Fix 1 - Clean up the image component
The first way to solve this problem is to clean up the image components. This can be done by running another DISM command. Here's what needs to be done:
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Open an administrative command prompt.
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Type and press Enter.
Dism.exe /online /Cleanup-Image /StartComponentCleanup
Once this is done, you can retry running the command to enable .NET Framework (Step 5 of Step 4 of Exploration) and check the status of the issue. If there is no difference in the situation, check fix 2.
Fix 2 – Restore command using DISM
DISM is known as a potential tool for repairing corrupted Windows system images. You can check, scan, and restore Windows system image health using DISM commands. To resolve this issue, you can run the restore command. Methods as below:
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Open an administrative command prompt.
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Type and press Enter.
Dism /Online /Cleanup-Image /RestoreHealth
- Then retry the command again to enable .NET Framework (Step 5 of Step 4 of Exploration). It should be fine this time.
--------------------Dividing line--------------------
.NET Framework installation self-repair tool provided by Microsoft
The official .NET Framework Repair tool published by Microsoft. This free tool can be used to troubleshoot problems installing .NET Framework or to repair existing .NET Framework installations. Apart from this, the tool also helps to suppress other known issues with .NET Framework installation by applying relevant fixes. Although it has a simplified GUI, advanced users can run it directly through the command prompt.
Microsoft .NET Framework Repair Tool download link
The method of using the tool is very simple, just follow the prompts. There are prompts for each step. Just read the hint text carefully.
It should be noted that if the tool comes to the following interface, don't rush to close it.
Instead, switch windows to try to open .NET Framework. If successful, just click Finish. If still unable to enable/update/repair .NET Framework installation, click "Next" to collect logs and send them to Microsoft for analysis.
eggs
The following four commands are shared. These four commands are common. If there is a suspected problem with the computer system, you can execute these four commands one by one in order (must be executed as an administrator). Sometimes it can solve the problem. Of course, interested friends can also learn about the execution behavior of these four commands. I won't go into details here.
然后鼠标右键单击开始按钮（微软图标的按钮）→"cmd（管理员)(A ）”→输入：
（WIndows11中可能显示Windows 终端（管理员））
sfc /SCANNOW
（按下Enter键）
Dism /Online /Cleanup-Image /ScanHealth
（按下Enter键）
Dism /Online /Cleanup-Image /CheckHealth
（按下Enter键）
DISM /Online /Cleanup-image /RestoreHealth
（按下Enter键）
If the following results appear, it means that the system files are normal.
Microsoft Windows [版本 10.0.19044.2130]
(c) Microsoft Corporation。保留所有权利。
C:\WINDOWS\system32>sfc /SCANNOW
开始系统扫描。此过程将需要一些时间。
开始系统扫描的验证阶段。
验证 100% 已完成。
Windows 资源保护未找到任何完整性冲突。
C:\WINDOWS\system32>Dism /Online /Cleanup-Image /ScanHealth
部署映像服务和管理工具
版本: 10.0.19041.844
映像版本: 10.0.19044.2130
[==========================100.0%==========================] 未检测到组件存储损坏。
操作成功完成。
C:\WINDOWS\system32>Dism /Online /Cleanup-Image /CheckHealth
部署映像服务和管理工具
版本: 10.0.19041.844
映像版本: 10.0.19044.2130
未检测到组件存储损坏。
操作成功完成。
C:\WINDOWS\system32>DISM /Online /Cleanup-image /RestoreHealth
部署映像服务和管理工具
版本: 10.0.19041.844
映像版本: 10.0.19044.2130
[==========================100.0%==========================] 还原操作已成功完成。
操作成功完成。
C:\WINDOWS\system32>
This concludes my sharing, thank you!