macOS High Sierra includes a new feature that requires user approval before loading any third party's kernel extension, including the one installed with the Egnyte Connect Desktop App.
Egnyte's kernel extension is used to serve up a fully functional file system that is populated with content from the cloud without the user needing to store every file that they have access to on their machine.
Steps to ensure you can use the Desktop App in macOS High Sierra
After installing the Egnyte Connect Desktop App, you may see a message titled 'System Extension Blocked' for a system extension signed by 'Egnyte Inc.' (similar to what is shown in the screenshot below)
If you see this, you will need to navigate to System Preferences > Security & Privacy and approve Egnyte's kernel extension by selecting the 'Allow' option next to the message saying that system software from Egnyte was blocked. To do this, you will have to ensure you click the padlock icon on the bottom left of the window to allow changes.
This approval UI is only present in the Security & Privacy preferences pane for 30 minutes after the alert. Until the user approves the KEXT, future load attempts will cause the approval UI to reappear in the Security & Privacy preferences but will not trigger another user alert.
For more information on this and how it affects Enterprise App distribution, see Apple's technical note on the topic.