I’ve been running into the error message on the right (“Unable to get property ‘style’ of undefined or null reference”) when opening an instance or a new tab of IE10 for the past couple of weeks. It didn’t matter what start page I used, since I tried about:blank, google.com and approximately a dozen more. I found out McAfee SiteAdvisor was the cause of this error pretty quick, but since the company I’m currently in doesn’t allow users to disable SiteAdvisor and I needed IE10 for some testing purposes, I had to find a different solution to the problem.
I found a workaround which will do for now: in IE10, go to ‘Tools’ then ‘Compatibility View Settings’ and check ‘Display all websites in Compatibility View’. This will, as you imagined, open all pages in Compatibility View which causes the errors to stop popping up. It is not an ideal solution, but it’s better than closing a script error message for every single IE instance or tab that is opened. Besides, it’s pretty easy to get IE to render as true IE10 in stead of Compatibility View by changing the browser mode to IE10 in the F12 developer tools.
Good to know: after changing browser mode to normal IE10 in a tab, the error doesn’t occur in that tab for the current or subsequent pages you visit while it maintains the Browser Mode. Of course new instances and new tabs will have Compatibility View enabled again.
Hope this helps