I was able to successfully load websites using the Unity Web Player plugin up until this morning.
I rebooted my machine this morning, got a Chrome automatic update, and now I see this whenever I try to go to a web page containing a Unity Web Player file.
No matter how many times I try to reinstall the Unity Plugin, it never is recognized by Chrome (works just fine in Firefox and Opera). And I consistently see the message that the plugin is not installed when I go to Unity Real-Time Development Platform | 3D, 2D, VR & AR Engine in the Chrome browser:
Everything worked yesterday with my previous version of Chrome for Windows chrome version 41.0.2272.118 m and version 5.0.1f1 of the Unity Web Player Plugin. And other browsers on the same computer (Opera and Firefox) are working just fine with the Unity Web Player Plugin version 5.0.1f1
It appears the Unity Web Player plugin version 5.0.1f1 is completely broken in this new updated version of Chrome for Windows version 42.0.2311.90 m.
Here’s an example of a Unity Web Player environment if anyone wants to test it:
Typing “chrome://flags/#enable-npapi” into Chrome will temporarily re-enable support.
See the NPAPI deprecation: developer guide for more information.
“In April 2015 (Chrome 42) NPAPI support will be disabled by default in Chrome and we will unpublish extensions requiring NPAPI plugins from the Chrome Web Store. All NPAPI plugins will appear as if they are not installed, as they will not appear in the navigator.plugins list nor will they be instantiated (even as a placeholder). Although plugin vendors are working hard to move to alternate technologies, a small number of users still rely on plugins that haven’t completed the transition yet. We will provide an override for advanced users (via chrome://flags/#enable-npapi) and enterprises (via Enterprise Policy) to temporarily re-enable NPAPI (via the page action UI) while they wait for mission-critical plugins to make the transition. In addition, setting any of the plugin Enterprise policies (e.g. EnabledPlugins, PluginsAllowedForUrls) will temporarily re-enable NPAPI.”
I believe that Google have now removed support for the WebPlayer in Chrome.
Edited to add link: