I broke RDi - Cannot start it

I was attempting to open a large XML file in the eclipse XML perspective. Eclipse/RDi froze and I closed the app.
Now RDi will not start.
Tried doing the -Clean start; as admin; and still not getting it.

I get a window 'An error has occurred. See the log file C:\Users\ .... Etc .

The .log file shows the following....

!SESSION 2019-02-05 09:54:01.958 -----------------------------------------------
eclipse.buildId=unknown
java.fullversion=8.0.5.20 - pwa6480sr5fp20-20180802_01(SR5 FP20)
JRE 1.8.0 Windows 10 amd64-64-Bit Compressed References 20180731_393394 (JIT enabled, AOT enabled)
OpenJ9 - bd23af8
OMR - ca1411c
IBM - 98805ca
BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=en_US
Framework arguments: -product com.ibm.rational.developer.ibmi.product.ide
Command-line arguments: -os win32 -ws win32 -arch x86_64 -product com.ibm.rational.developer.ibmi.product.ide

This is a continuation of log file C:\Users\therrp\IBM\rationalsdp\workspace\.metadata\.bak_0.log
Created Time: 2019-02-05 09:54:16.733

!ENTRY org.eclipse.core.resources 2 10035 2019-02-05 09:54:16.733
!MESSAGE The workspace exited with unsaved changes in the previous session; refreshing workspace to recover changes.

!ENTRY com.ibm.etools.iseries.rse.ui 1 0 2019-02-05 09:54:22.542
!MESSAGE Rational Developer for i product plugin version 9.6.5.v20181129_2145

!ENTRY org.eclipse.e4.ui.workbench.swt 4 2 2019-02-05 09:55:17.320
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.e4.ui.workbench.swt".
!STACK 0
java.lang.IllegalArgumentException: Argument cannot be null
at org.eclipse.swt.SWT.error(SWT.java:4514)
at org.eclipse.swt.SWT.error(SWT.java:4448)
at org.eclipse.swt.SWT.error(SWT.java:4419)
at org.eclipse.swt.widgets.Widget.error(Widget.java:482)
at org.eclipse.swt.widgets.Widget.checkParent(Widget.java:291)

.... Etc.

Any help appreciated.

Paul Therrien
(203) 854-9400
Ext: 2230
ptherrien@xxxxxxxxxxx<mailto:ptherrien@xxxxxxxxxxx>

+++++ This email and related attachments may contain confidential information intended exclusively for the addressee. Unauthorized use, disclosure or distribution of this material is prohibited. If you received this message in error, please advise the sender and delete all copies of it. Content is provided by the individual sender and does not necessarily reflect the views of the Company. Though sender believes this transmission to be virus-free, it is the recipient's responsibility to ensure that it is.