I have a problem with opening a project

There's a folder called Library in your project. It stores a cache of assets converted to something Unity understands, but you can delete it without losing anything; Unity will just recreate it. Deleting the Library folder has saved me from that problem once; I guess there was something corrupted in that folder. Other than that, do you have any Asset Importer or Asset Postprocessor script in your project? Maybe there's a bug that causes an infinite loop in one of them.