"Good practice is to back up your Sitecore's <Folder-ends-with-dev.local> so that you can use this backup whenever you encounter an error."

"Do not override the Sitecore's web.config with your Project's web.config."

This error arises because your project's web.config file overwrites the Sitecore's web.config.

For a solution, refer to the blog post "Exception from HRESULT: 0x80131040".

One suggestion: this error can be easily resolved by installing NuGet Packages. However, if you observe that your project's web.config contains only 60-70 lines, while Sitecore's web.config contains more than 900 lines, it indicates that the most effective way to resolve this error is by replacing the Sitecore's web.config with the original Sitecore's web.config.

For more information, please visit the Sitecore's website for further details.