Steve on 17 Jul, 2017 12:14 PM
welcome to the GPGTools support platform. Sorry you are having problems using GPG Suite.
The first beta of macOS 10.13 High Sierra has been released by Apple in early June. GPGMail will be disabled upon upgrade. We're already looking into the internal changes.
This KB-article has details as to why GPGMail becomes disabled after major macOS updates.
For any productive work and if you rely on using GPGMail, you should refrain from updating to the pre-release version of macOS. At this time we cannot say, when a first test version for macOS 10.13 High Sierra will be available.