# OPC writeValues Async **URL:** \ **Category:** Ignition\ **Tags:** ignition81\ **Created:** [November 3, 2025, 8:14pm UTC](https://forum.inductiveautomation.com/t/opc-writevalues-async/111910 "2025-11-03T20:14:06Z")\ **Posts on this page:** 1\ **Showing post:** 5
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [November 3, 2025, 8:49pm UTC](https://forum.inductiveautomation.com/t/opc-writevalues-async/111910/5 "2025-11-03T20:49:17Z")
Sounds like Vision? If so, also be sure to **not** write to any UI properties or call any UI methods from such a background thread. Use `system.util.invokeLater()` and friends to send information/progress back to the foreground. Failure to follow this rule will eventually yield mysterious client crashes or unending freezes. More info: > [@Update GUI via Asynchronous thread](https://forum.inductiveautomation.com/t/update-gui-via-asynchronous-thread/9666): > > I’ve got a script I am experimenting with that can take a lot of time to execute, so I now use the system.util.invokeAsynchronous to run the script in a separate thread to keep the GUI from locking up. I am using the asynchronous thread to copy files from one place to another, and I would like to show the progress of the file copy with a progress bar. How would I go about this? I am importing a few python libraries to do this. import shutil def fileTransfer(): path = system.file.openFile() … (Still relevant for Vision.) --- _[View the full topic](https://forum.inductiveautomation.com/t/opc-writevalues-async/111910)._