Unity Editor deleted everything in Heirarchy

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Not really sure what to say. Unity is starting to piss me off. This happened last week and I ended up having to remake everything. Backed it up this time so I’m going to work from that but I still want to know why it happens and how do I stop it from happening ? I opened Unity up “used default layout” and then everything was gone

EDIT : FORGOT TO SAY RIGHT BEFORE THIS HAPPENED BOTH TIMES IT SAID THE UNITY EDITOR LAYOUT COULDN’T BE OPENED

thanks guys