Visual Studio updated and will not launch project to any web browser

Thanks for reaching out! Here are some steps which are helpful

1. Check All Output and Log Messages: Check the Output window in Visual Studio for any error messages or clues as to what's happening when you try to launch your project.
2. Verify Browser Debugging Tools:
   • Ensure that your browser (like Edge or Chrome) is set as the default web browser in Visual Studio. You can right-click on your project in Solution Explorer, select "Properties", and check the 'Web' tab for the start action.
3. Reset Visual Studio Settings:
   • Sometimes resetting Visual Studio to its default settings can resolve issues that arise from updates. You can do this by going to Tools > Import and Export Settings > Reset all settings.
4. Reinstall or Repair Visual Studio:
   • If you're still facing issues, consider repairing your Visual Studio installation through the Visual Studio Installer. Sometimes, configurations may get corrupted during updates.
5. Check for Windows Updates:
   • Like Thao suggested, check if there were any recent Windows updates that could affect Visual Studio. Sometimes, rolling back a recent Windows update can help if it’s causing compatibility problems.
6. Run Visual Studio as Administrator:
   • Try running Visual Studio in administrator mode. Right-click the Visual Studio shortcut and select "Run as Administrator."
7. Web Server Configuration:
   • Ensure that your project's web server settings are correct (IIS Express or Kestrel) and that IIS Express isn't encountering issues.
8. Clear Temporary Files:
   • Navigate to the folder where Visual Studio's temporary files are stored and clear them. This is typically located in a path like %LocalAppData%\Microsoft\VisualStudio\<version>\WebApps.

tldr:

manually remove the update KB5066128 using a admin version of CMD:

wusa /uninstall /kb:5066128

this resolves the problem.

I had tried

dism /online /cleanup-image /restorehealth

sfc /scannow

It takes a log time to check all the files. It found some problems, but didn't resolve this problem.

I looked in the event logs and saw this install last night:

Installation Started: Windows has started installing the following update: 2025-10 Cumulative Update for .NET Framework 3.5 and 4.8.1 for Windows 11, version 25H2 for x64 (KB5066128)

Removing that patch fixes the issue that you can't run debug in any browser.

I have the same problem (same day as you). I was already on the latest version, so it might be another update?