LabVIEW UI Freezes When Using SMTP Send VI

Updated Apr 29, 2020

Reported In


  • LabVIEW 2017

Operating System

  • Windows

Issue Details

  • My LabVIEW UI freezes when I try to send emails from LabVIEW using the SMTP Send VI. After the email has been sent, the UI is updated again without freezing.¬†
  • My LabVIEW Front Panel does not update when sending an e-mail. Why does this happen?
  • My LabVIEW code hangs when the STMP Send VI is executing. How do I prevent this?


When sending an email from LabVIEW the corresponding VI is executed in the so-called UI Thread. Among other purposes, the UI Thread is responsible for updating the LabVIEW UI. During the sending of an email all other UI actions are paused until the email has been sent.

To overcome this issue you can use following alternatives: