Thanks @mlauber71 for the advice.
I added -clean, and this led to another error on startup. KNIME no longer starts, and this message is displayed in the logfile in the configuration subdirectory:
!ENTRY org.eclipse.osgi 4 0 2020-07-06 12:30:24.985
!MESSAGE Application error
!STACK 1
java.lang.UnsatisfiedLinkError: org.eclipse.swt.internal.C.PTR_sizeof()I
at org.eclipse.swt.internal.C.PTR_sizeof(Native Method)
at org.eclipse.swt.internal.C.<clinit>(C.java:19)
at org.eclipse.swt.widgets.Display.<clinit>(Display.java:140)
at org.eclipse.ui.internal.Workbench.createDisplay(Workbench.java:765)
at org.eclipse.ui.PlatformUI.createDisplay(PlatformUI.java:160)
at org.knime.product.rcp.KNIMEApplication.createDisplay(KNIMEApplication.java:205)
at org.knime.product.rcp.KNIMEApplication.start(KNIMEApplication.java:105)
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:498)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:653)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:590)
at org.eclipse.equinox.launcher.Main.run(Main.java:1499)
This issue seems similar to the one raised here, but the two resolutions suggested didn’t work. Using -clean was what created the problem (and it persists even if I now remove -clean again). My -Dequinox.statechange.timeout is 30000 by default, so changing it to 10000 doesn’t resolve it either.
Is there a possibility that this is all antivirus software related? This is a work machine for which I don’t have administrator rights, but I could have our IT Support team look into whitelisting the KNIME application.