Problems after upgrade to Windows 10 Pro 17763.503

Hi

I'm running Windows 10 Pro, version 17763.503. I'm converting an old Classic asp site to a .Net C# Razor site. Consequently, I need access to the old asp site to review functionality before recoding it. I have built the Classic asp site on my development laptop and all has been running well for years now. The site is running in production at a few clients and also on my demo web site which is hosted by my ISP. All sites are working except the dev site on my laptop.

Some weeks ago (24 April to be exact) Windows prompted me to install an upgrade which I duly did - to version 17763.503. The upgrade went smoothly but immediately afterwards I noticed that the old Classic asp site on my dev laptop stopped working in Edge, IE11, FF or Chrome. Specifically, it was taking 30 seconds or more to open the site, not rendering the css (I use a version of Bootstrap 3 called Smarty which I purchased for its themes) and when it eventually displays the home page, on clicking the link to navigate to the log in page, that page fails to load. No real coding error is ever displayed except that the page normally says something like "The page cannot be displayed" and "ERR_CONNECTION_RESET" or "INET_E_DOWNLOAD FAILURE", depending on the browser. All is OK with the database connection and data calls etc. so its not a database error or connection error.

I contacted Microsoft Help Desk and after being handed over through 5 different consultants (I'm bald now from tearing my hear out) and hours of watching them fiddle here and there on my laptop, they couldn't explain it so they just arrogantly ended it all by saying they've tested their software extensively and are satisfied that it is working and therefore the problem must lie with my application. I don't buy it because minutes before I applied the Windows upgrade my Classic asp app was working in ALL browsers, and just minutes after the upgrade it was failing in ALL browsers. The cynic in me says that Microsoft has deliberately started introducing changes that will culminate in them stopping support for Classic ASP and this is their way of forcing change. Incidentally, the new Razor site is running with the same Bootstrap and database and is running well.

Event viewer reports this error in "System" but I can't seem to see what triggers it throughout the day. I tried one suggestion to change the permissions on the APPID but that didn't change anything:
The application-specific permission settings do not grant Local Activation permission for the COM Server application with CLSID
{8E240CF7-3017-494D-877D-7D19548A3142}
and APPID
{F72671A9-012C-4725-9D2F-2A4D32D65169}
to the user ACER\hende SID (S-1-5-21-1995079702-3253873399-167814391-1001) from address LocalHost (Using LRPC) running in the application container Unavailable SID (Unavailable). This security permission can be modified using the Component Services administrative tool.

So what else have I tried?
* Tweaking various browser settings, deleting the cached files & cookies etc.
* Tweaking various settings in IIS; deleting the web site and recreating it.
* Adding more features for "Internet Information Service" in "Turn Windows features on and off" in the hope that this would trigger some change to IIS on Windows 10 Pro.
* Creating a new user with Admin rights.
* Running sfc /scannow. No errors were reported.
* Running DISM /Online /Cleanup-Image / RestoreHealth. No errors were reported.
* Downloading a fresh version of Windows 10 Pro iso and re-installing Windows.
* Flushing the DNS.
* Tested using other laptops running on Windows 10 and Windows 2008 Server, connecting via my local network to my development site, both work correctly using all browsers.
* Tested the production site of the Classic ASP app, which is published on the Internet (same code and database as I'm running on my development laptop), using my laptop and the others metioned above, and all work correctly. My conclusion therefore is that the problem doesn't lie with the browsers, or the Classic asp app's code or the css, but with the Windows 10 Pro OS that's failing to render style sheets correctly when served from the local ISS (localhost) to browsers on the local PC.
* If I exclude all FIVE links to css sheets in the app it responds and loads as quickly as normal (without styling of course).
* I created a new 1-page Classic asp test app/site to emulate the app's css link to the same relative css folder location as the Bootstrap css, but with a simple custom-made style sheet with one property in it, and database connection. The test app worked correctly.
* I then linked the test app to the FIVE Bootstrap css style sheets that the production app uses. The test app fails to render the css.
* I ran all the Bootstap style sheets through W3School's CSS Validation Service and fixed all reported errors. The error still persisted thereafter.
* I eliminated reference to all but the main style sheet and then placed a single custom css property at the very top so that I could see it rendered in the test app, and then deleted all other 8000 odd rows of the style sheet. No error was found. My custom property was visible and rendered correctly.
* I then incrementally added 100 rows of Bootstrap css code back and tested after each. Initially the error didn't occur, but after reaching around 2600 rows the error started occurring, but not consistently, so I was never able to actually pinpoint a specific css property that was causing the error. Even after rolling back 300 or more rows, the error persisted, despite the fact that it had previously worked with 2300 rows of css code. So this wasn't a reliable indicator at all. As a result, after hours of back and forth testing I gave up with this.
* I installed a new clean version of the Bootstrap 3 and then the Bootstrap 4 css product from the vendor, but the problem still remains.

My conclusion, Windows 10 Pro version 17763.503, has a bug that prevents it from serving complex, long, multi-page, style sheets to browsers on the local PC. Surely I can't be the only one in the world to be experiencing this?

Any help will be greatly appreciated.

Hello Caledon Ken
Sadly, I didn't delay updates nor did I uninstall the update. I did try reverting to a restore point but I think by that time it was after the Microsoft "consultants" had made so many changes that it didn't fix anything.

- - - Updated - - -

Hello bro67
I'm running on Windows Pro 10 and the problem is on my local development machine, not with the ISP's server. "Send errors to browser" is set to true, but the problem doesn't display any errors, it just simply seems to ignore the CSS, but even that is not true because it does render my simple testing css page, just not the complex Bootstrap css. Like I said, all was working perfectly just minutes before the Windows update installation, but it was broken immediately after. I'll try posting my sorry thesis on one of your other suggested forums. Thanks for your help.

Hello Ken
Thanks for that tip. I'll definitely look into it because it seems Windows is unreliable. Another example, just earlier today I needed to open my Accounting software program (this is the first time I've done so since that fateful Windows update) and guess what, the program files were corrupted. Now I recall the Windows re-install process specifically said my other files and data would not be affected when I did the re-install. They lie! Anyway, fortunately that problem was soon resolved by re-installing the software. Thanks again.