# Launch Client Jar Invalid Error

**URL:** <https://forum.inductiveautomation.com/t/launch-client-jar-invalid-error/115993>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [June 16, 2026, 12:24am UTC](https://forum.inductiveautomation.com/t/launch-client-jar-invalid-error/115993 "2026-06-16T00:24:19Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![farjam\_haghighi](https://avatars.discourse-cdn.com/v4/letter/f/f08c70/32.png) [@farjam\_haghighi](https://forum.inductiveautomation.com/u/farjam_haghighi)\
**Post date:** [June 16, 2026, 12:24am UTC](https://forum.inductiveautomation.com/t/launch-client-jar-invalid-error/115993/1 "2026-06-16T00:24:20Z")

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![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/7/b/7ba731c134860c5f9f01c989a5b6d1f6807d488a.png)  
I'm getting this Error trying to open a designer, I have checked the windows security and there is nothing being blocked. I have also tried deleting the Cache folder contents. Any suggestions what can be done next?

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**Author:** ![Arnaud\_Declerck](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/arnaud_declerck/32/44872_2.png) [@Arnaud\_Declerck](https://forum.inductiveautomation.com/u/Arnaud_Declerck)\
**Post date:** [June 16, 2026, 5:43am UTC](https://forum.inductiveautomation.com/t/launch-client-jar-invalid-error/115993/2 "2026-06-16T05:43:38Z")

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Hi @farjam_haghighi ,

I think this would help you

> [@Launch client jar invalid](https://forum.inductiveautomation.com/t/launch-client-jar-invalid/109145):
>
> Testing Ignition 8.3.0 Beta. I had to upgrade my Designer Launcher to 1.3.0 Beta-1 to access the 8.3 designer. However, I'm now unable to open any of my other 8.1.23 designers; I receive a "Launch client jar invalid" message. I ended up downgrading my designer, but this means I can no longer access 8.3. Has anyone else encountered this issue?

Regards

Arnaud

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**Author:** ![justinedwards.jle](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/justinedwards.jle/32/37854_2.png) [@justinedwards.jle](https://forum.inductiveautomation.com/u/justinedwards.jle)\
**Post date:** [June 21, 2026, 7:15am UTC](https://forum.inductiveautomation.com/t/launch-client-jar-invalid-error/115993/3 "2026-06-21T07:15:45Z")

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I've seen this error when trying to open an 8.1.x project with an 8.3.x launcher. The solution is to download the older designer launcher from the applicable gateway and reinstall it. If both launchers are needed, simply rename your 8.3 launcher's shortcut, so it won't be overwritten when 8.1's is reinstalled.