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Windows 10 Upgrade and IIS 503 Errors

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I just upgraded one of my machines to Windows 10 from Windows 8.1. This is a development machine and it has a ton of IIS Web sites and virtuals on it. The Windows upgrade (build 10162) went very smooth and everything seems to be working rather well – all except for IIS.

Accessing any link on the local machine I get this lovely error:

503 Server Unavailable

It looked like IIS was installed properly and the service is running. I can use IISReset to restart IIS and I can see the admin service running. Application Pools are also showing running, but any attempt to access any IIS page results in an immediate 503 error.

After some spelunking around in the Event Viewer I found that the problem is the IIS Rewrite Module:


This is the IIS Rewrite Module that gets separately installed from the Web Platform Installer.

IIS Rewrite Module Problem

It turns out that there's a new version available that's more recent (but doesn't change the version number), and that needs to be installed in order to work. The version I found on the WebPI was dated a month ago (5/27/2015), and I suspect it's meant to address just the type of problem I've been running into with my upgrade.

To install the module:

  • Uninstall the Rewrite Module from Windows Features
  • Go to the Web Platform Installer
  • Pick Url Rewrite from Products | Server section and install
  • Restart IIS

And bingo – my IIS installation is up and running again.

Several people tweeted mentioning that they ran into these problems repeatedly with successive Windows 10 updates, so it's quite possible that the issue has to do with settings rather than an old version. Before going through the above steps you might want to just try to Repair the UrlRewrite installed feature.


Watch for External Module Updates

In searching around I found a few other reports of people having issues with external module updates  in IIS. So if your server fails with errors:

  • Check the Event Log
  • See if errors relate to any external Modules not installed by the main IIS install
  • Do a Repair Install or Uninstall Reinstall the Module if there are newer versions

Windows 10 seems to have done a pretty good job updating most of my Windows components, including all native IIS components and Web sites. However, in this case the Rewrite module is externally installed from WebPI so it's not a standard Windows file and therefore wasn't updated. This can be a sleeper bug depending on the components you are dealing with. Essentially – double check anything that was installed through Web PI and make sure it all still works since those external components did not get updated in the Windows 10 migration.

Posted in IIS  Windows  

The Voices of Reason


July 06, 2015

# re: Windows 10 Upgrade and IIS 503 Errors

Hi Rick,

at iis.net forum I found solution to fix urlrewrite module.

Machine: Windows 10,x64, build 10130
IIS 10.0 urlwrite fix

Open Regedit > HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\InetStp
Edit "MajorVersion" and set the "DECIMAL" value to 9
Hit F5 while in Regedit
Now go install the ReWrite 2.0 module:


Change the "MajorVersion" back to "DECIMAL" value of 10 (HEX= a)
Hit F5 while in Regedit Close Regedit

Run> inetmgr
URL Rewrite icon is finally visible.

Ian Trembirth
July 29, 2015

# re: Windows 10 Upgrade and IIS 503 Errors

Updated to the release version yesterday and the problem came up but your solution fixed the issue!

Thanks for posting what you've found!

August 01, 2015

# re: Windows 10 Upgrade and IIS 503 Errors

Rick! I owe you a lunch. Thanks so much for the help....

Hudson Alves
August 05, 2015

# re: Windows 10 Upgrade and IIS 503 Errors

Thank you Rick, I had this problem when migrating from Win 7 to Win 10. easily resolved.

August 05, 2015

# re: Windows 10 Upgrade and IIS 503 Errors

Another thank you from me!

Andrea Bizioli
August 06, 2015

# re: Windows 10 Upgrade and IIS 503 Errors

I had the same problem: I tried to repair the URL Rewrite module but got an error, so I uninstalled it. When trying to install the new version 2.0 it says that it's required IIS version >= 7.0

I installed the IIS 80. Express but it keeps saying that plus IIS seems unreachable when typing localhost on my browser.

Any suggestion?
Thanks a lot

September 22, 2015

# re: Windows 10 Upgrade and IIS 503 Errors

Rick, your the real MVP! Thanks for posting your findings - saved me an afternoon of trial and error.

September 27, 2015

# re: Windows 10 Upgrade and IIS 503 Errors

As you said... Bingo! Thank you!

November 17, 2015

# re: Windows 10 Upgrade and IIS 503 Errors

For anyone else running into this recently... I had to do this back in August when I first upgraded to W10. Then it happened again yesterday (Nov 16) when I did the major W10 update. Same fix both times. Uninstall rewrite module. Reinstall. Fixed. I tried repair and no dice.

But obviously this problem has not been fixed by Microsoft.

December 22, 2015

# re: Windows 10 Upgrade and IIS 503 Errors

Yes, same here - as per my earlier comment above from Sept 2015 when I initially upgraded to Windows 10. I'm here once again with the same problem after the big Windows 10 update. Thanks again Rick! I'm glad this page was still here.

April 12, 2016

# re: Windows 10 Upgrade and IIS 503 Errors

Thanks. Just upgraded from Windows 8 to 10. Got this same problem and simply repairing the module solved the problem.

May 05, 2016

# re: Windows 10 Upgrade and IIS 503 Errors

I was having the same error problem but persistence prevailed!

On Windows 64bit you also need to edit the "Wow6432Node"


Frustrating little detail....

Adam Senour
May 09, 2016

# re: Windows 10 Upgrade and IIS 503 Errors

First of all, as others have pointed out, this post is AWESOME. This probably saved me about 8-10 hours of guessing horribly at the problem.

One oddity that I noticed in my particular case, and I'm not sure if anyone else has noticed this. I noted the version number of the IIS URL Rewrite module before I uninstalled it, and it was 7.2.2. When I downloaded the newer version of the module from WPI, I noticed that the version number was 7.2.1952. I'm guessing this means that this specific problem was fixed at some point in one of those 1950 builds, although narrowing it down might be tricky!

Anyway, thanks again, Rick!

Harvey Mushman
June 08, 2016

# re: Windows 10 Upgrade and IIS 503 Errors

I've been away for a month... just went back to start work again on a system that was working perfectly when I turned off the machine and this 503 Error bit me in the ass! Followed the instructions and fixed! Rick your problems and write ups are an awesome time saver! Thanks as always...

September 29, 2016

# re: Windows 10 Upgrade and IIS 503 Errors

My windows 10 got updated and the IIS start giving me 403 error. 5001 5031 WAS errors. ApplicationPool does not start due to several error. I think the update changed some files and IIS could to run properly. I just uninstalled IIS , .net 3.5 and 4.5, restarted and reinstalled all back and selected option to download files from Microsoft server. I think that downloaded all compatible files. But even it broke all the bindings, so I need to recreate the Bindings for every website. Worked!!!

Harvey Mushman
September 13, 2017

# re: Windows 10 Upgrade and IIS 503 Errors

It happened again... F...ing MS !

After not using localhost for the past couple of months on one of my laptops, I just returned only to find that all access to localhost resulted in a 503 error. After spending an hour or so hunting around, I decided to turn to the old faithful help center - West-Wind.com/Support and low and behold... Rick saved my ass once again! This is the second time this has happened to me, one would think I would have learned! Thank you for all you do to support us with these wonderful writings.

January 01, 2019

# re: Windows 10 Upgrade and IIS 503 Errors

Hi Rick - I wish I had the luck of some of the others... I'm in over my head on this one but here's the progress: I set up my home W10 Pro as a server and FTP works great. Remote Desktop works great. I setup up IP following and that works great and finally I set up a website in IIS and that worked great BUT the next day I got the dreaded 503 error and have been working it ever since (about 30 hours so far). I did your fix and no help. Looking at the Event Viewer I still get the DistributedCOM 10016 Error which says:

The application-specific permission settings do not grant Local Activation permission for the COM Server application with CLSID and APPID {9CA88EE3-ACB7-47C8-AFC4-AB702511C276} to the user DESKTOP-4L2V4RC\bizib SID (S-1-5-21-3086862884-1539808275-1596629730-1001) 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.

I focused in on the Component Services tool and accepted registering the Computer (it asked). I started looking at the help and as a hardware engineer, I figured it was time to seek some help. I did the IISreset and reboot and still the same error. Lost - why did it work and then give 503 the next day? What to do to get it to ever work again as an http server?

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