Using the HTML Editor version 12.5 build 406 every time I do a preview with the F11 key my preview shows up fine but the other day when I close the preview window I get an "Unable to Navigate Error" I attached a screenshot of the error....any ideas?

I've had that a few times. I've been trying to replicate it on a regular bases but am not there yet.

First thing I would recommend is to update to the current version of the program. I "believe" that issue was fixed in the update (don't hold me to that though, but I'm pretty sure it was one of the reported issues and was fixed). Let us know if that fixes the issue for you.

I have been experiencing this exact problem. So I just paid for the current version and opened a page in it, I find that the preview freezes and the program becomes unresponsive. If they fixed the problem they didn't get it right. Looks like I wasted my money.

Try setting the shortcut properties to run as admin.

If you "paid" for an update then you definitely wasted your money since all updates are free for all of CoffeeCup's software other than full rewrites (Flash to HTML/CSS) stuff which this one isn't of that nature.

My guess is you have a nasty script running on the page that is messing up the preview, which does happen periodically even in expensive web editors. Try commenting out any/all the scripts on your page and see if that fixes the issue. Then uncomment them one at a time to see try to track down which one is causing the problems and try working out what might be wrong with the script or ask in the forums here once you know what's causing it. It's most likely a script doing it though.

If you paid for the program again you'll need to open a support ticket with CoffeeCup on if you can get reimbursed for that or not. That's not something the user forums can help with.

He just paid for the current version. I don't think he had it already.

Well I'm assuming he paid for the "current" version "again" because he said he was having the same problem SO he got the current version Who knows lol.

Which way is it Bruce?
Did you pay for the free update or just downloaded the software and got you cart in front of the horse.

Updated to version 12.7 and the error no longer appeared during preview