I am running into a problem editing a role that feels like a bug, but I wanted to ask as a sanity check. I am running vSphere 22.214.171.124000 and using the HTML5 client.
(yes, I know 6.5 is old. Upgrading is managed by others, I can't do anything about it)
I go to Administration -> Access Control -> Roles, select the role I want to change (which is a locally created role, not one of the default roles), and click "Edit role action" (the pencil). In the Edit Role dialog box, I select the permissions group on the left, and select the permissions I want to add/remove on the right, then click Next. On the next page, when I click Finish, I get a circled red ! on the Role name line, and if I click the circled red !, it says "Role name is already in use". It does not seem to be specific to this role, I've gotten this error when trying to edit several different roles, on multiple vSphere servers.
It's like it's trying to add a new role even though I clicked Edit role action and the dialog box says Edit Role.
I definitely have Administrator permissions. I can add, remove, and clone roles. I've been able to modify roles in the past, although the last time would have been before we upgraded to 126.96.36.199000.
Have you tried other browsers (Firefox ESR, Waterfox, Edge) or versions of your browser.
You could also try the web client (Flash), but this requires a browser that works with Adobe Flash.
Personally I use the following combination and I only use it for the connection to VMware vSphere .65, not for surfing the internet.
Firefox ESR 38.8 (32bits)
Adobe Flash player 188.8.131.52
Both software must be installed without internet access (temporarily) and then must be configured not to update.