The official ISO files for Windows 10 PC Insider build 14342 are now available for download. You can grab them directly from Microsoft, which will allow you to perform a clean install of the latest build available for PC users on the Slow ring.
Windows 10 build 14342 was released to Slow ring insiders in mid-May, bringing a number of features from the upcoming Anniversary update. Do be aware that, once downloaded, you'll have to transfer the ISO file to a DVD or USB flash drive to perform a clean install. You can check out instructions for doing just that, along with the ISO files themselves, at the Microsoft link below.