Am getting this error in the log when I try to run 8.2
!SESSION 2018-10-25 14:15:53.717 -----------------------------------------------
eclipse.buildId=unknown
java.version=1.8.0_25
java.vendor=Oracle Corporation
BootLoader constants: OS=macosx, ARCH=x86_64, WS=cocoa, NL=en_AU
Framework arguments: -keyring /Users/username/.eclipse_keyring
Command-line arguments: -os macosx -ws cocoa -arch x86_64 -keyring /Users/username/.eclipse_keyring
!ENTRY org.eclipse.osgi 4 0 2018-10-25 14:16:31.502
!MESSAGE Application error
!STACK 1
java.lang.NoClassDefFoundError: org/eclipse/core/resources/ResourcesPlugin
at org.eclipse.emf.ecore.plugin.EcorePlugin.getWorkspaceRoot(EcorePlugin.java:1131)
at org.eclipse.emf.ecore.resource.impl.ExtensibleURIConverterImpl.<clinit>(ExtensibleURIConverterImpl.java:393)
at org.eclipse.emf.ecore.resource.impl.ResourceSetImpl.getURIConverter(ResourceSetImpl.java:499)
at org.eclipse.emf.ecore.resource.impl.ResourceSetImpl.getResource(ResourceSetImpl.java:369)
at org.eclipse.e4.ui.internal.workbench.ResourceHandler.getResource(ResourceHandler.java:289)
at org.eclipse.e4.ui.internal.workbench.ResourceHandler.loadResource(ResourceHandler.java:265)
at org.eclipse.e4.ui.internal.workbench.ResourceHandler.loadMostRecentModel(ResourceHandler.java:169)
at org.eclipse.e4.ui.internal.workbench.swt.E4Application.loadApplicationModel(E4Application.java:377)
at org.eclipse.e4.ui.internal.workbench.swt.E4Application.createE4Workbench(E4Application.java:252)
at org.eclipse.e4.ui.internal.workbench.swt.E4Application.start(E4Application.java:148-)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:388-)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:673)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:610)
at org.eclipse.equinox.launcher.Main.run(Main.java:1519)
Caused by: java.lang.ClassNotFoundException: org.eclipse.core.resources.ResourcesPlugin cannot be found by org.eclipse.emf.ecore_2.12.0.v20160420-0247
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:461)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:372)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:364)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:161)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 22 more
---- UPDATE ----
Deletion of old install and a clean install fixes this as per advice from support below.