After upgrading Symantec Endpoint Protection (SEP) client from on-prem 14.2.1031.0100 to cloud 14.2.3332.1000, you see "Application Error 3" when viewing the client under Help > Troubleshooting it shows not connected and that client is not enrolled into cloud. This appears to happen only on Windows 7 machines.
Windows 7 64-bit machine
Symantec is aware of this issue and will update this document when a solution becomes available. It is not necessary to log a support case on this issue. Please subscribe to this article to be notified of any updates.