# WindowsTableHeaderUI error on client 7.9.3

**URL:** <https://forum.inductiveautomation.com/t/windowstableheaderui-error-on-client-7-9-3/56046>\
**Category:** General Discussion\
**Created:** [February 11, 2022, 6:47pm UTC](https://forum.inductiveautomation.com/t/windowstableheaderui-error-on-client-7-9-3/56046 "2022-02-11T18:47:42Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mike.miller](https://avatars.discourse-cdn.com/v4/letter/m/ee59a6/32.png) [@mike.miller](https://forum.inductiveautomation.com/u/mike.miller)\
**Post date:** [February 11, 2022, 6:47pm UTC](https://forum.inductiveautomation.com/t/windowstableheaderui-error-on-client-7-9-3/56046/1 "2022-02-11T18:47:42Z")

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I’m having an issue that just popped up today. I’m not able to view any tables in my client. They just won’t load. When I look at Help → Diagnostics → Console, I see several errors starting with the following error.

Exception in thread “AWT-EventQueue-0” java.lang.NoClassDefFoundError: com/sun/java/swing/plaf/windows/WindowsTableHeaderUI

The machine I’m running this client on is running fedora 35 so I tried launching a virtual windows machine and everything works fine and another guy in the office is running mac OS and he isn’t having any trouble. I’ve been using this machine for a while and haven’t had any trouble until today. Any suggestions on where to go from here?

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**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [February 11, 2022, 6:49pm UTC](https://forum.inductiveautomation.com/t/windowstableheaderui-error-on-client-7-9-3/56046/2 "2022-02-11T18:49:42Z")

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Are you sure the version of Java (being used by Ignition) is the same?

> [@Some projects not working on PI](https://forum.inductiveautomation.com/t/some-projects-not-working-on-pi/38675):
>
> I tried a few different examples I found to get ignition on a Pi 4, and I can get most of it to work. However I have some projects that have a popup and won’t load. There is a popup “Unable to pen window XXXXX” with these details… SerializationException: Error deserializing element “\<c” caused by NoClassDefFoundError: com/sun/java/swing/plaf/windows/WindowsTableHeaderUI caused by ClassNotFoundException: com.sun.java.swing.plaf.windows.WindowsTableHeaderUI Ignition v7.9.14 (b2020042813) J…

> [@\[BUG-14674\] Raspberry Pi Serialization Problems on Window with Power Table](https://forum.inductiveautomation.com/t/bug-14674-raspberry-pi-serialization-problems-on-window-with-power-table/27233):
>
> SerializationException: Error deserializing element "\<c" caused by NoClassDefFoundError: com/sun/java/swing/plaf/windows/WindowsTableHeaderUI caused by ClassNotFoundError: com.sun.java.swing.plaf.windows.WindowsTableHeaderUI Ignition v7.9.12 (b2019070213) Java: Rasbian 11.0.3 I get this error when trying to open a window with a power table in it. The only place in the table that uses java swing is my header configuration, but even when I disable the configureHeaderStyle I get the same error.