SQL Server download:
One is to download directly from the official website: then install it directly (there are detailed tutorials on the Internet)
The other can be downloaded from other websites, I recommend: https://msdn.itellyou.cn/ For specific tutorials, please refer to https://blog.csdn.net/weixin_46585199/article/details/118073611
SQLServer uninstallation:
Click win+r, then enter control to enter the control panel: Control Panel>Programs>Programs and Features
From here, uninstall all the programs installed last time (the publisher of all programs is Microsoft Corporation, and they were all installed at the same time, so if you don’t know which programs are installed, you can delete them according to these two items, basically no Mistakenly deleted!)
Some programs may not be deleted temporarily, and follow-up operations directly:
Same Win+r, enter regedit, open the registry, delete the following:
1. Find: HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager, delete the item "PendingFileRenameOperations" on the right
2. Delete all subkeys about Microsoft SQL Server under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
3.删除HKEY_CURRENT_USER\SOFTWARE\Microsoft\Microsoft SQL Server
4. Delete HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer
5. Delete the following folders: C:\Program Files\Microsoft SQL Server and C:\Program Files(x86)\Microsoft SQL Server
If you are worried about whether the deletion is clean, I recommend two softwares here: windows install clean up and Total Uninstall. windows install clean up can delete the files and registry settings that constitute the Windows Installer configuration information of the selected program. The registry is deleted together
The links are as follows: https://pan.baidu.com/s/1WB7PCct89BeL3H1HOzDZqA?pwd=45xs https://pan.baidu.com/s/1rXXP8QHs_chgW4nFJoNVvw
After deleting, you can see that all the services about SQL are gone (Win+R enter services.msc to enter the server):
After SQL Server is reinstalled, the error is still reported:
Could not open key: UNKNOWN\Components\7ABFE44842C12B390AF18C3B9B1A1EE8\000021599B0090400100000000F01FEC.
Verify that you have sufficient access to that key, or contact your support personnel.
The underlined part is random. The reason for the error is that there is no permission when accessing the registry. The solution is as follows:
win+r enter regedit, enter the registry, find HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>windows>CurrentVersion>Installer>UserData>S-1-5-18>Components
Right click on Components, click Permissions, click Advanced
Then just be sure. Re-open setup.exe and install it.