Fixing the 'Process with an Id of #### is not Running' Error in Visual Studio

Approach 1

1. Close Visual Studio: Ensure that Visual Studio is completely closed before proceeding.
2. Delete the Hidden .vs Folder
   • Navigate to the folder where your solution files are stored.
   • Find the hidden .vs folder and delete it. You may need to enable viewing hidden files in File Explorer to see this folder.
3. Delete the bin and obj Folders
   • Search within your project directory for the bin and obj folders.
   • Delete these folders to ensure that old build artifacts are cleared.
4. Restart Visual Studio: After deleting the folders, reopen Visual Studio.
5. Rebuild and Debug
   • Press F5 or click the "Start Debugging" button to rebuild the project.
   • IIS Express should load normally, allowing you to debug your application.

Approach 2

Open Visual Studio as Administrator: To avoid permission issues, right-click on the Visual Studio icon and select Run as administrator.

Unload the Project

• In Solution Explorer, right-click on your project.
• Click on Unload Project to temporarily unload it.

Edit the .csproj File

Right-click on the unloaded project again and select Edit PROJECT_NAME.csproj (replace PROJECT_NAME with the actual name of your project).

Remove the IIS Express Configuration

In the .csproj file, locate the following lines of code.

<DevelopmentServerPort>45678</DevelopmentServerPort>
<DevelopmentServerVPath>/</DevelopmentServerVPath>
<IISUrl>http://localhost:45678/</IISUrl>

Delete these lines to remove the custom port settings.

Save and Close the .csproj File: After making the changes, save the file and close it.

Reload the Project

Right-click the unloaded project again and select Reload Project.

By following these steps, you can reset your project's IIS Express configuration and resolve port-related issues.