IBM Rational Software Architect - No application id has been found

I needed to switch my RSA from version 9.0 to 8.5.5.
IBM Installation Manager doesn't have a downgrade option, so I uninstalled the current version and installed the required one. Starting RSA I saw this

!SESSION 2014-04-15 16:41:04.514 -----------------------------------------------
eclipse.buildId=unknown
java.fullversion=JRE 1.7.0 IBM J9 2.6 Windows 7 x86-32 20130617_152572 (JIT enabled, AOT enabled)
J9VM - R26_Java726_SR5_20130617_1436_B152572
JIT  - r11.b04_20130528_38954ifx1
GC   - R26_Java726_SR5_20130617_1436_B152572
J9CL - 20130617_152572
BootLoader constants: OS=win32, ARCH=x86, WS=win32, NL=en_US
Framework arguments:  -product com.ibm.rational.rsa4ws.product.v90.ide
Command-line arguments:  -os win32 -ws win32 -arch x86 -product com.ibm.rational.rsa4ws.product.v90.ide

!ENTRY org.eclipse.equinox.app 0 0 2014-04-15 16:41:05.692
!MESSAGE Product com.ibm.rational.rsa4ws.product.v90.ide could not be found.

!ENTRY org.eclipse.osgi 4 0 2014-04-15 16:41:33.441
!MESSAGE Application error
!STACK 1
java.lang.RuntimeException: No application id has been found.
at org.eclipse.equinox.internal.app.EclipseAppContainer.startDefaultApp(Unknown Source)
at org.eclipse.equinox.internal.app.MainApplicationLauncher.run(Unknown Source)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(Unknown Source)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(Unknown Source)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(Unknown Source)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Unknown Source)
at org.eclipse.equinox.launcher.Main.basicRun(Unknown Source)
at org.eclipse.equinox.launcher.Main.run(Unknown Source)

at org.eclipse.equinox.launcher.Main.main(Unknown Source)

The shortcut to RSA was not properly updated leading to launching the wrong version. Updating part of the target field from 
com.ibm.rational.rsa4ws.product.v90.ide
to 
com.ibm.rational.rsa4ws.product.v85.ide
solved the problem.