@volcaidon – Sorry to hear that, but it is highly unlikely our plugin is the main cause. It may be part of the issue, but a more likely cause is that your menus simply have a ton of items in them or a lot of plugins that added custom fields for menu items.
Unfortunately this is a known issue with WP core itself. The way it saves menus is all at once. Servers have a max amount of info you can submit at once, and a large menu with lots of extra field data can easily go over that limit.
Large menus generally have lots of side effects as well like loading slow in the editor.
That said I highly recommend you either prune your menus down to more manageable sizes or consider if there are other plugins that are also adding extra fields to menu items that aren’t needed.
Generally speaking our plugin isn’t the only one that adds stuff to the menu editor, so it could simply also be that another plugin, theme or multiple have fields there too, and ours simply pushed you over the limits of your host/server.
Happy to debug with you but this plugin won’t crash a site or make menus load slow on its own, only with compounded issues from other sources could it have such an effect, but obviously in those cases its not really the problem, just part of a larger issue.