# JUCE port of legacy vst3 plugin not recognized in vst3 host as the old plugin

**URL:** <https://forum.juce.com/t/juce-port-of-legacy-vst3-plugin-not-recognized-in-vst3-host-as-the-old-plugin/32704>\
**Category:** Audio Plugins\
**Created:** [April 5, 2019, 6:55pm UTC](https://forum.juce.com/t/juce-port-of-legacy-vst3-plugin-not-recognized-in-vst3-host-as-the-old-plugin/32704 "2019-04-05T18:55:07Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![markg](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@markg](https://forum.juce.com/u/markg)\
**Post date:** [April 5, 2019, 6:55pm UTC](https://forum.juce.com/t/juce-port-of-legacy-vst3-plugin-not-recognized-in-vst3-host-as-the-old-plugin/32704/1 "2019-04-05T18:55:08Z")

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Working on porting a legacy VST SDK based vst3 plugin to JUCE. It builds and runs fine on its own but when opening legacy sessions in a vst3 host (Studio One 4 for example), it is not recognized as the same plugin even though the name is identical. Does anyone know what IDs etc. have to be declared to make the host think this new JUCE version is the same as the old VST SDK plugin? Thank you.

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**Author:** ![broose](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/broose/32/3381_2.png) [@broose](https://forum.juce.com/u/broose)\
**Post date:** [April 5, 2019, 8:43pm UTC](https://forum.juce.com/t/juce-port-of-legacy-vst3-plugin-not-recognized-in-vst3-host-as-the-old-plugin/32704/2 "2019-04-05T20:43:39Z")

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perhaps ensure that the “Plugin Manufacturer Code” and related data is identical between your two projects.

![44%20PM](https://us1.discourse-cdn.com/flex026/uploads/juce/original/2X/e/e6c5596f431d2396479522c41c4801d743aa86e3.png)

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**Author:** ![markg](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@markg](https://forum.juce.com/u/markg)\
**Post date:** [April 5, 2019, 9:23pm UTC](https://forum.juce.com/t/juce-port-of-legacy-vst3-plugin-not-recognized-in-vst3-host-as-the-old-plugin/32704/3 "2019-04-05T21:23:06Z")

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Well the old project was not a JUCE project so I don’t know what the equivalent values would be.

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**Author:** ![broose](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/broose/32/3381_2.png) [@broose](https://forum.juce.com/u/broose)\
**Post date:** [April 5, 2019, 9:34pm UTC](https://forum.juce.com/t/juce-port-of-legacy-vst3-plugin-not-recognized-in-vst3-host-as-the-old-plugin/32704/4 "2019-04-05T21:34:44Z")

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Open up the contents of your old .vst project file, take a look at the Info.plist file, and find the discrepancies between your new project and your old project. If your plist matches, I’m pretty sure hosts will open your new VST as if it were the old one.

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**Author:** ![markg](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@markg](https://forum.juce.com/u/markg)\
**Post date:** [April 5, 2019, 10:22pm UTC](https://forum.juce.com/t/juce-port-of-legacy-vst3-plugin-not-recognized-in-vst3-host-as-the-old-plugin/32704/5 "2019-04-05T22:22:50Z")

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Thanks. I got it working by finding the use of the VST macro #define INLINE\_UID(l1, l2, l3, l4) in the original project and then modifying the JUCE VST wrapper to do something similar with the same IDs.