I factory-reseted a 450G which my ISP used as CPE.
I updated to the latest version some days ago, 6.35.2.
When trying to login to WebFig it seems to be broken and with a different design (See screenshot).
Can I reinstall webfig ?
Looks like some old cache.
Use Netisntall http://wiki.mikrotik.com/wiki/Manual:Netinstall and format device it should fix this issue.
First try flushing the browser cache. Or just try from another browser or another computer to see if that fixes it.
I had the same issue on RB433AH, and I can confirm that after reinstalling RouterOS with Netinstall fixes the issue. You can keep old configuration by checking “Keep old configuration” checkbox.