Browser freezes when editing main menu

Hi everyone!

I'm setting my new blog with the writer theme and for the 2nd time after the reinstall main menu editing causes crashing problems. I have the same experience in Firefox, Safari and Chrome.
I've installed the quick install version, deleted some of the categories and their respective posts and than started editing main menu. After i've managed to change the order of the items in the main menu for 4-5 times, every time i try to click on the main menu customization option everything freezes.
I also did the complete reinstall - the problem re-appears in the exact same manner. So i guess deleting my website and launching it over and over again isn't the best option...

Help would be appreciated!

Anyways, i'm getting the following message when trying to acces costumization>writer theme>menus>main menu -

& this after clicking "debug"

Hi,

Could you please provide me with a URL to your website and back-end access via PM (click the “Private Message” text underneath my avatar) so that I may analyze it? Because I can't see this issue on my Writer theme installation.

You can also use Appearance -> Menus section from your admin panel (not in Customizer) to edti your menu.

That maybe will not be necessary! I think the problem was causing one specific thing - i deleted some categories which comes with the quick install option, but didn't remove them from the main menu.

After i did a fresh reinstall (3rd in a row), i removed categories from the main menu and at the end deleted them from the site under posts>categories. So far everything works ok, but i will be monitoring everything for 1-2 days and give you guys an update!

Tnx.