As you all know when you open the site of App Invetor it shows you the last project you have modified. Before i just wanted to modify one of my project but the page gives me an error that says " Out of Memory" and that error obligates me to refresh the page but it is still giving me he same writing. Can you explain me the problem? Thanks (I hope the message is grammatically correct 
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You've likely created too many screens in your project. You can access App Inventor without loading the most recent project by using the URL http://ai2.appinventor.mit.edu/?autoload=false. However, you will likely continue to be unable to access the project since each screen requires a decent amount of memory to be loaded. Others might be able to help you consolidate your screens if you export your project and post it here.
To export a project without opening it, check the box next to it in the project list, and look for the Project->Export option.
thanks a lot
But is there a way I can open the project or i have lost it ?
There are tools to do surgery on exported .aia files.
Some Power Users do this manually.
If you have been using Chrome, you may want to try Firefox instead. There seems to be a potential issue in Chrome's SVG engine that causes it to use more memory for the same blocks workspace versus Firefox. Sometimes people have better experiences if they switch browsers.