Can't open project in IntelliJ IDEA, it stucks as "loading..."

Problem

When trying to open a project via File | Open or File | Recent Projects, it hangs in "loading...".

Resolution

Try the following workarounds:

• If the issue is led by a corrupted plugin, then disable all 3rd party plugins via Settings | Plugins | ⚙ | Disable all downloaded plugins
• If the issue is led by a corrupted project, then close the IDE, open your project in OS file explorer and remove all *.iml files and the .idea folder from your project. Note: .idea folder mainly contains the caches, search history, UI settings, so in most cases, it's safe to delete and re-create it. One important exception are shelved files. If you use IDE "shelve" command in your daily work, the shelved files by default are saved in .idea subfolder of your project folder.
• If the issue is reproduced on WSL (Windows system for Linux), check the workaround in Directory tree not loading in Open File or Project Window
• If the issue is led by an inaccessible network-mounted directory, then check the workaround in Redesign file chooser dialog

If it doesn't help, Contact support with collected logs (Help | Collect Logs and Diagnostic Data).

See also: IDE freezes when open project via File->Open