Problem with eclipse 2020-03 and manifest files

I tried to import a project from github into my eclipse working directory and suddenly it broke everything. I've reinstalled eclipse and the SDK but for some reason the manifest files are not loading correctly. When I try to setup a run configuration both the device and target SDK show "invalid". When I look at a manifest file (from my working projects) it generates an error in eclipse and is unable to read them.  I've attached an image of the error and I'm wondering if anyone has seen this before.

Thanks.

Full text:

org.eclipse.core.runtime.AssertionFailedException: assertion failed:
at org.eclipse.core.runtime.Assert.isTrue(Assert.java:113)
at org.eclipse.core.runtime.Assert.isTrue(Assert.java:99)
at org.eclipse.ui.part.MultiPageEditorPart.setActivePage(MultiPageEditorPart.java:1030)
at org.eclipse.ui.forms.editor.FormEditor.setActivePage(FormEditor.java:616)
at org.eclipse.ui.part.MultiPageEditorPart.createPartControl(MultiPageEditorPart.java:337)
at org.eclipse.ui.internal.e4.compatibility.CompatibilityPart.createPartControl(CompatibilityPart.java:154)
at org.eclipse.ui.internal.e4.compatibility.CompatibilityEditor.createPartControl(CompatibilityEditor.java:96)
at org.eclipse.ui.internal.e4.compatibility.CompatibilityPart.create(CompatibilityPart.java:361)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:58)
at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:1002)
at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:967)
at org.eclipse.e4.core.internal.di.InjectorImpl.internalInject(InjectorImpl.java:139)
at org.eclipse.e4.core.internal.di.InjectorImpl.internalMake(InjectorImpl.java:408)
at org.eclipse.e4.core.internal.di.InjectorImpl.make(InjectorImpl.java:331)
at org.eclipse.e4.core.contexts.ContextInjectionFactory.make(ContextInjectionFactory.java:202)
at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.createFromBundle(ReflectionContributionFactory.java:91)
at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.doCreate(ReflectionContributionFactory.java:60)
at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.create(ReflectionContributionFactory.java:42)
at org.eclipse.e4.ui.workbench.renderers.swt.ContributedPartRenderer.createWidget(ContributedPartRenderer.java:132)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createWidget(PartRenderingEngine.java:1002)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:662)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:768)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$0(PartRenderingEngine.java:739)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:733)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:717)
at org.eclipse.e4.ui.workbench.renderers.swt.StackRenderer.showTab(StackRenderer.java:1297)
at org.eclipse.e4.ui.workbench.renderers.swt.LazyStackRenderer.lambda$0(LazyStackRenderer.java:75)
at org.eclipse.e4.ui.services.internal.events.UIEventHandler.lambda$0(UIEventHandler.java:38)
at org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:236)
at org.eclipse.ui.internal.UISynchronizer.syncExec(UISynchronizer.java:133)
at org.eclipse.swt.widgets.Display.syncExec(Display.java:4561)
at org.eclipse.e4.ui.internal.workbench.swt.E4Application$1.syncExec(E4Application.java:219)
at org.eclipse.e4.ui.services.internal.events.UIEventHandler.handleEvent(UIEventHandler.java:38)
at org.eclipse.equinox.internal.event.EventHandlerWrapper.handleEvent(EventHandlerWrapper.java:205)
at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:203)
at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:1)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:234)
at org.eclipse.osgi.framework.eventmgr.ListenerQueue.dispatchEventSynchronous(ListenerQueue.java:151)
at org.eclipse.equinox.internal.event.EventAdminImpl.dispatchEvent(EventAdminImpl.java:132)
at org.eclipse.equinox.internal.event.EventAdminImpl.sendEvent(EventAdminImpl.java:75)
at org.eclipse.equinox.internal.event.EventComponent.sendEvent(EventComponent.java:44)
at org.eclipse.e4.ui.services.internal.events.EventBroker.send(EventBroker.java:55)
at org.eclipse.e4.ui.internal.workbench.UIEventPublisher.notifyChanged(UIEventPublisher.java:63)
at org.eclipse.emf.common.notify.impl.BasicNotifierImpl.eNotify(BasicNotifierImpl.java:424)
at org.eclipse.e4.ui.model.application.ui.impl.ElementContainerImpl.setSelectedElementGen(ElementContainerImpl.java:170)
at org.eclipse.e4.ui.model.application.ui.impl.ElementContainerImpl.setSelectedElement(ElementContainerImpl.java:188)
at org.eclipse.e4.ui.internal.workbench.ModelServiceImpl.showElementInWindow(ModelServiceImpl.java:661)
at org.eclipse.e4.ui.internal.workbench.ModelServiceImpl.bringToTop(ModelServiceImpl.java:625)
at org.eclipse.e4.ui.internal.workbench.PartServiceImpl.delegateBringToTop(PartServiceImpl.java:790)
at org.eclipse.e4.ui.internal.workbench.PartServiceImpl.showPart(PartServiceImpl.java:1263)
at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditor(WorkbenchPage.java:3195)
at org.eclipse.ui.internal.WorkbenchPage.lambda$9(WorkbenchPage.java:3100)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:72)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:3098)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:3068)
at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:3051)
at org.eclipse.ui.internal.ReopenEditorMenu.open(ReopenEditorMenu.java:284)
at org.eclipse.ui.internal.ReopenEditorMenu.access$1(ReopenEditorMenu.java:268)
at org.eclipse.ui.internal.ReopenEditorMenu$1.lambda$0(ReopenEditorMenu.java:232)
at org.eclipse.swt.events.SelectionListener$1.widgetSelected(SelectionListener.java:84)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:252)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4105)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1037)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3922)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3524)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1160)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1049)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155)
at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:658)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:557)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:154)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:150)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:137)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:107)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:401)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:657)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:594)
at org.eclipse.equinox.launcher.Main.run(Main.java:1447)