Don't Install if You Aren't Prepared
Make sure you are prepared before you install the macOS Mojave beta. If you don't spend time planning, you may find yourself missing files, photos and losing loads of time to an issue.
As I mentioned, macOS 10.14 problems are to be expected, and if you don't prepare your Mac and yourself there is a bigger chance that you will run into issues.
Specifically, you need to make sure you have a good backup before you install macOS Mojave. This is the best way to protect your files and the easiest way to downgrade from macOS Mojave to macOS High Sierra if you have problems.
We'll share a full list of things you should do before you install the macOS Mojave beta soon, which will help you prepare if you are thinking about using the public beta.