constract 3 project won't open

Hello

I go to the project and there

what did I do wrong?

maybe not saved correctly?

it is possible to fix it?

Press F11 when you see this error, and check errors messages in the console log.

so i just go into full screen

you probably confused the button

and even if I find the problem in console log, how can I fix it?

press F12 (console). Not F11 (Fullscreen).

See the error message in the console. Post it here.

Switch to Console tab and check last errors there.

what should I do?

This kind of problem seems to happen pretty often... it's a bit scarry, even if I try to make backup every times.

Any prevention to avoid this kind of major issue Ashley ?

It's impossible to help without knowing how the problem occurs in the first place. If you can find the steps to reproduce the problem and make a project go from openable to unopenable, please file an issue - otherwise there's no way we can help.