Here you can find the most common known issues for the current & older noted x64 preview builds which depending on the issue might have a suggested workaround especially if it helps to avoid any crash issues. Also please consider reporting any issues via any of the available contact options so repeated issues not already noted can be looked into & resolved sooner.

Note: If you've gotten here from the link on the About preference page from a beta build then you need to see the appropriate beta build thread on the forum for information specific to it & also to re-read the beta tester sign-up information as you've not completed the required beta tester setup process.