Problem/Motivation
When using the IIS web server, Drupal core is caching the 404 page not found error page, if the URL referrer has a space (or %20) at the end. EG. https://example.com/%20
Can't be reproduced on Nginx, or Apache.
Steps to Reproduce:
(from comment #33)
1) Enable drupal core cache or if already enabled then Clear all your cache.
2) Then visit your homepage_url/%20 (www.website.com/%20) or any URL/%20 before visiting any other page.
you will get 404 page(This depends on your server mostly IIS gets 404)
If you get 404 then only you can reproduce this issue.
3) Then visit your homepage or that URL(entered in 2) You will get 404.
Proposed resolution
Patch: #35
Remaining tasks
* reviews needed
* needs tests
* Possibly update IIS documentation
Original report by rhouse
Original title: "Page not found for home page"
This discussion thread seems to be an unreported bug. It just happened to me. Unlogged in users get a page not found on the home page. Clearing the cache fixes it. Since then I turned off page caching since I cannot afford to have this site down. I don't yet know if the problem will recur.
http://drupal.org/node/1097528
PS: page.module for "Component" is a guess on my part - it could be anywhere.