We have a project running on Sitefinity 7.1, which we've been running for years (since 4.x) and haven't had this issue before.
Recently I upgraded to Windows 10, configured IIS to have all the right Handlers etc. as per Progress's recommendations and I get to the point where the site runs successfully.
The problem is on the backend. When I browse to /sitefinity it correctly redirects me to dev.customer.com/.../Login (note: dev.customer.com is based on an entry in my hosts file).
I enter my credentials and click login after which it redirects me back to /sitefinity and throws a 404 error.
If however I manually add /Pages behind /Sitefinity, it correctly displays the pages backend page. I can edit and publish/save pages, news items and blogs, etc. So the problem seems specifically related to the /Sitefinity page. If I manually add a '/' behind /Sitefinity it correctly redirects me to the dashboard page.
The only thing I can think of is that one of my rewrite rules are causing this issue. Here are my rules:
Final note: On our production server this issue doesn't exist , which is Windows Server 2012 Standard/IIS 8.0
Any help would be appreciated