https://learn.microsoft.com/en-us/answers/questions/5585563/localhost-not-working-anymore-after-2025-10-cumula Skip to main content This browser is no longer supported. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. Download Microsoft Edge More info about Internet Explorer and Microsoft Edge Add Add Share via Facebook x.com LinkedIn Email Localhost not working anymore after 2025-10 cumulative update Windows 11 [svg] Jan van Rhijn 110 Reputation points 2025-10-15T12:01:18.59+00:00 Hi, Since the last cumulative update of 2025-10 I can not access applications via localhost anymore. It looks like I am not the only one with this issue: https://serverfault.com/questions/1193405/ http-2-protocol-error-after-windows-update and https:// stackoverflow.com/questions/79790827/ localhost-applications-failing-after-installing-2025-10-cumulative-update-for-w When the update (KB5066835) is removed, everyhting works again. This is affecting local development as well as business applications Cheers, Jan Windows for business | Windows 365 Business Windows for business | Windows 365 Business [logo_windo] Sign in to follow Follow Sign in to follow Follow question 3 comments Hide comments for this question Report a concern I have the same question I have the same question 19 {count} votes 1. [svg] Jan van Rhijn * Follow 110 Reputation points 2025-10-15T14:09:07.8366667+00:00 On a fresh install of Windows (and updated to the latest version), I don't have this issue anymore. I am checking what the differences are between my current Windows and the freshly installed one. Can more people verify that this issue is resolved on a fresh install of Windows? 0 votes Report a concern 2. [svg] Vic Omundsen * Follow 0 Reputation points 2025-10-15T16:57:38.7666667+00:00 Uninstalling KB5066835 worked for me. 0 votes Report a concern 3. [svg] Colby Butler * Follow 0 Reputation points 2025-10-15T21:55:11.88+00:00 I apologize if this has already been answered, but since I've rolled back to a version before [KB5066835], is it likely that a patch will be available when I check for Windows updates? I've paused updates for now, so I want to ensure I don't miss a potential fix. 0 votes Report a concern --------------------------------------------------------------------- Sign in to comment Add comment [en-us ] Comment Use comments to ask for clarification, additional information, or improvements to the question. [ ] [ ] Discard draft Add comment 20 answers Sort by: Most helpful Most helpful Newest Oldest 1. [svg] Yigit Yildirim * Follow 40 Reputation points 2025-10-15T13:22:51.67+00:00 Hi, What action is expected from Microsoft? Are you planning to release a new Windows update to fix the issue, and if so, when is it expected? Thanks Please sign in to rate this answer. Yes No 11 people found this answer helpful. 2 comments Show comments for this answer Report a concern 1. [svg] Odai Al Halaiqa * Follow 0 Reputation points 2025-10-15T15:23:02.8133333+00:00 The steps below worked with me to solve the issue of Microsoft Update October 14, 2025--KB5066835 (OS Builds 26200.6899 and 26100.6899) o run CMD as Administrator o execute these commands wusa /uninstall /kb:5066835 wusa /uninstall /kb:5065789 wusa /uninstall /kb:5066131 o restart the machine o after the restart, download this tool https://download.microsoft.com/download/f/2/2/ f22d5fdb-59cd-4275-8c95-1be17bf70b21/wushowhide.diagcab o run it and click on hide windows update and select the update, usually this one KB:506683,5, and try Or disable Windows Update after you uninstall the update and restart 0 votes Report a concern 2. [svg] Realizer * Follow 0 Reputation points 2025-10-15T16:26:40.5633333+00:00 Has anyone found a solution? I've tried all the methods in this discussion, but they didn't work. wusa /uninstall /kb:5065789 This update cannot be uninstalled, and I get the message "The installer encountered a problem." 2 votes Report a concern ----------------------------------------------------------------- Sign in to comment Add comment [en-us ] Comment Use comments to ask for clarification, additional information, or improvements to the question. [ ] [ ] Discard draft Add comment 2. [svg] Yigit Yildirim * Follow 40 Reputation points 2025-10-15T13:28:27.26+00:00 This is the fix that works for our applications: Uninstalling the following KBs wusa /uninstall /kb:5066835 wusa /uninstall /kb:5065789 restart computer Please sign in to rate this answer. Yes No 5 people found this answer helpful. 4 comments Show comments for this answer Report a concern 1. [svg] Cristiano Larghi * Follow 0 Reputation points 2025-10-15T13:57:21.9633333+00:00 wusa /uninstall /kb:5066835 write an error removing the KB and exit. Is not possible (for me at least) remove this KB. EDIT: I have removed window sandbox, then I have uninstalled successfully both KB and now works, thanks! 0 votes Report a concern 2. [svg] Mantas Grubliauskis * Follow 0 Reputation points 2025-10-15T17:32:43.0633333+00:00 Thank you, this worked for me 0 votes Report a concern 3. [svg] Brayan Villatoro * Follow 0 Reputation points 2025-10-15T19:03:58.83+00:00 Worked! Thanks. 0 votes Report a concern 4. [svg] Tony Perez * Follow 0 Reputation points 2025-10-15T19:16:30.9266667+00:00 This worked for me, thanks 0 votes Report a concern ----------------------------------------------------------------- Sign in to comment Add comment [en-us ] Comment Use comments to ask for clarification, additional information, or improvements to the question. [ ] [ ] Discard draft Add comment 3. [svg] MICKEY LYSHOLM NIELSEN * Follow 5 Reputation points 2025-10-15T13:15:28.2833333+00:00 Added the keys here as well but it dosn't solve the problem. Please sign in to rate this answer. Yes No 2 people found this answer helpful. 1 comment Show comments for this answer Report a concern 1. [svg] Jason Chu * Follow 0 Reputation points 2025-10-15T13:26:53.8166667+00:00 The keys also didn't fix it for me. 0 votes Report a concern ----------------------------------------------------------------- Sign in to comment Add comment [en-us ] Comment Use comments to ask for clarification, additional information, or improvements to the question. [ ] [ ] Discard draft Add comment 4. [svg] AD * Follow 0 Reputation points 2025-10-15T13:27:36.7366667+00:00 uninstalling KB5066835 did not fix, but uninstalling KB5066835 and KB5065789 did fix. Please sign in to rate this answer. Yes No 2 people found this answer helpful. 1 comment Show comments for this answer Report a concern 1. [svg] Steven Hsiao * Follow 0 Reputation points 2025-10-15T14:17:24.73+00:00 This work for me 0 votes Report a concern ----------------------------------------------------------------- Sign in to comment Add comment [en-us ] Comment Use comments to ask for clarification, additional information, or improvements to the question. [ ] [ ] Discard draft Add comment 5. [svg] Harry Hamilton * Follow 10 Reputation points 2025-10-15T13:31:29.1366667+00:00 Tried multiple possibilities... User's image User's image Even tried the suggestion in StackOverFlow User's image Rebooted after each attempt and still doesn't work. Please sign in to rate this answer. Yes No 2 people found this answer helpful. 1 comment Show comments for this answer Report a concern 1. [svg] Knut Hunstad * Follow 0 Reputation points 2025-10-15T13:40:22.7366667+00:00 Same here. And I also tried starting Chrome with --disable-http2, but that didn't help either. Our application goes to a localhost-URL at the end of the sign-in process, which shows "Page not found" now. 0 votes Report a concern ----------------------------------------------------------------- Sign in to comment Add comment [en-us ] Comment Use comments to ask for clarification, additional information, or improvements to the question. [ ] [ ] Discard draft Add comment * * 1 * ... * 1 * 2 * 3 * 4 * ... * 4 * Sign in to answer Your answer [en-us ] Answer Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem. 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