Currently, the 64-bit version of the Mozilla Firefox browser is not supported for use with the vSphere Web Client and Client Integration Plugin.
To resolve this issue, use an alternative supported browser or install a 32-bit version of the Mozilla Firefox browser.
Supported Windows Browsers are:
- Microsoft Internet Explorer 10.0.19 and later
- Google Chrome 39 and later (32-bit only)
- Mozilla Firefox 34 and later (32-bit only)