When I uninstalled Opera Developer I also deleted all user settings, I don't think so there are extensions active when I install it back

ok then is Opera Developer v26 x86. What to do?

As I wrote I installed Opera Developer v26 x64 on Windows 8. It's not opening the files, but the web pages or local opera customization pages (settings, plugins, flags, downloads ....) and tabs are in endless loops. That means web pages and opera customization pages can't be open in "Opera Developer's" tabs.

I installed the last version of Opera Developer x64 on Windows 8. When I run it, tabs won't load. I can't open bookmarks page as well, for an example setting page and other pages for opera developer's customization can't be loaded. How to fix that problem? Any ideas?