Well there were no direct changes in that area…
Is your WP installation up to date? And could you check for any javascript errors in the console when you click on the login button?

I am experiencing something similar, but have been able to narrow it down to this:

Login from Mac works fine

Login from PC using IE does not work 

Login from PC using Chrome or Safari works

Register from PC using IE works

Duplicated this with three separate PC’s – two using IE 8 and one using IE 9

IE 8:  “error” bottom left corner when trying to login

IE 9: “javascript:void(0) bottom left when trying to login

Any help is appreciated

Thanks

‘javascript:void(0)’ is what is should say in the status bar. The error would be interesting to know more about. Was there any further information?

Generally speaking of course this is working just fine for 99 % of users so we really need to determine what it is about your site that causes the problem. The most obvious thing that comes to mind would be an IE specific script that is being run just in that browser. This is not uncommon. There are many such scripts that can be added for IE to try and overcome the many shortcomings that IE suffers from. So – do you know if there is anything like that being run by your WP theme or by one of your other plugins?

Thanks for the follow-up.  I wish I could answer your question, but all of that is relatively new/foreign to me.  The site is not “live” yet  – not sure if that could have a factor in it.  

How would I even begin to look for such a script?  I am using U-Design WP theme…..

Thanks!

Well I would probably run the page and then use the ‘View Source’ menu item to look at the html being generated and search for all .js files being loaded. See if there is one being loaded for IE that is not being loaded for other browsers…

not sure if this helps…

Also….I originally installed another plugin (Mingle) and the same person using the PC/IE was able to login.  It wasn’t until I switched over to SP that this began to occur.  

Where does Mingle handle the login? Does it supply a login form like SP does? In fact – are we talking about the SP login form here or the standard Wp login?

I cannot even remember how the login was handled on Mingle.  I only used it for a few hours, but I do know others were able to log in with no trouble (including using a PC/IE).  

I am having trouble with the SP login.  What’s strange is that someone using a PC/IE is able to register, but they are unable to login.  

Did any of the scripts I posted previously help out?

Thanks

MC said
I cannot even remember how the login was handled on Mingle.  I only used it for a few hours, but I do know others were able to log in with no trouble (including using a PC/IE).

Well that is kind of important because I think you will find that Mingle just relies on logging in via the standard Wp login form so you can’t make the comparison with that and SP. The standard Wp login form – or a sidebar widget as Tal used above – is going to work because it is just a form – there is no scripting involved.

I am having trouble with the SP login.  What’s strange is that someone using a PC/IE is able to register, but they are unable to login.  

Not strange at all. The register button loads an html form – again – no scripting involved.

Did any of the scripts I posted previously help out?

No – they all seem harmless…

Out of interest – the login button uses the same code to open the form as the Advanced Search form button so if one fails then the search form should fail as well. Does it?

I wasn’t making a comparison of one product over the other, but rather trying to give you more clues/information to help solve my problem.  

I don’t believe the advanced search button is working either.  After logging out and searching on the Mac, I get a response (even though it turns up nothing).  When I try it on the PC/IE, nothing happens. 

I was meaning you can not compare the login function of the two.

I would guess you just have a script conflict and the fact that other browsers open the login window is probably down to the fact they use better javascript engines.

This codex article explains what this means and what to look for:

http://codex.simple-press.com/codex/faq/troubleshooting/what-is-this-jquery-conflict/

These things – if this is what it is – can usually be fixed up fairly easily.

Ok, I read that….but I still don’t have a firm grasp on this. If this is what it is, then what would be the fairly easy fix for it?

Usually the quickest way to try and figure this out is by temporarily switching WP themes back to a supplied one like Twenty-Eleven and see if it works. If not then disabling any plugins one-by-one and testing.

A lot of themes and plugins add stuff in thinking they are helping by using Google CDN Js, minimizing the JS, caching pages or adding in things for specific browsers like IE. By switching themes or deactivating plugins you can usually determine the one that is causing an issue.