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I have severe doubts that Opera would work if no other mainstream browsers would work. It sounds like this site checks for IE and if it doesn’t see technologies specific to IE (and I am guessing specifically the Windows version - meaning the old ancient version of IE for Mac won’t work), it just outright denies it and there isn’t going to be a fix.

Honestly it seems as if the website designer went out of their way for some reason to lock out other browsers for whatever reason and unless there is a major consumer backlash, there is likely little that you are you going to be able to do to change that.

And it really irks me, the web was never designed to lock you down to one technology that is closed source and is on one platform. MS’s monopolistic ways made it really popular to utilize technological ways to insulate their ecosystem and it’s very tough to break those habits. And the sad thing is that there is very little that you can do to stop it. Unless the company is a monopoly in the limited and strict legal sense and their methods are deemed the be a violation of trust (that’s something the feds are going to have to do), they are fully within their rights to set whatever rules they want for accessing a private portion of their site.
 
I don’t believe that he ever mentioned what type of bill it was so recommending a credit union would be useless if he was talking about, say a utility company. Or the place providing his housing.

But my recommendation is similar. If there is any way to avoid this company do it - if they don’t have a good enough view over technology to respect the simple reality that other web browsers and OS exist, I would seriously second guess their views on technology needs in general. Anybody who even considers an IE only website outside of a very good reason (and paying a bill doesn’t cut it - if my bank site can support other browsers, so can those guys) is in my mind horribly out of date and should not have inherent trust.

I suppose one option is to look into online bill pay - any decent bank is going to offer you let you pay a bill from a ton of different companies including utilities. They may not support everything like rental companies or state run things, but they may be able to offer a better alternative.
 
Set up auto payment at your bank.

No need to go to this unspecified (and probably non-existing) website.
 
Thanks for the suggestions.
Going to just set up auto-pay.
Just out of curiosity, Bootcamp shouldn't have a problem with that?
 
Just out of curiosity, Bootcamp shouldn't have a problem with that?

If you absolutely defiantly need to run IE to pay this bill, installing a copy of Windows 7 or 8 with Bootcamp will certainly solve your problem.
 
Thanks for the suggestions.
Going to just set up auto-pay.
Just out of curiosity, Bootcamp shouldn't have a problem with that?

My wife has a site she has to visit once a year using IE on Windows. It uses Activex. I installed (freeware) virtualbox and I dug around and found an old copy of WinXP with a key # and installed it in virtualbox. No money spent. About 12 GB of disk space "wasted" on her Mac but she can now use the site. No money spent for Parallels (current or older half price version). I did buy an OEM CD of Win 7 just to tinker (about $99 just before Win 8 came out). I also installed that under virtualbox and it worked fine. MS is going to EOL XP soon but it doesn't matter if the only time I run it is for her to use that antiquated site.
 
Any libraries in your area? Could be a free alternative aside from the travel to/from and possible security aspect.
 
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