We’ve just finished upgrading VMWare infrastructure from version 6.0 to version 6.5 and we’ve noticed that vSphere Web Client (Flash) is not working anymore with Firefox.
After accessing vCenter IP Address, we select vSphere Web Client (Flash) as in the screenshot
and we are getting the following error:
“Error: Error #2134
Our Firefox version is 70.0.1.
The solution is pretty straight forward, you have to modify only one parameter in Firefox configuration. Please check bellow the solution:
Step One – Open Firefox and modify parameter
Open Firefox browser and in the URL field, insert the text “about:config” and accept the warning.
In the top filter bar, enter “sandbox”, change dom.ipc.plugins.sandbox-level.flash from “3” to “0” and restart Firefox.
Step two – re-open vSphere
Now re-open vSphere Web Client (Flash) and you will be able to access vCenter without any problems.
That was all!