EPM 11.2: Explore Button Not Appearing

This is a post about an issue we had in our environment, it seems likely an Oracle Support document will be created for this problem but I just wanted to post it here as well. The fix wasn't actually discovered by me, but by a colleague.

The problem is that in Workspace on EPM 11.2 the Explore button simply does not appear. Inspecting the configtool logs shows errors like this:

...
[2020-01-02T16:23:04.675+00:00] [EPMCFG] [ERROR] [EPMCFG-07211] [oracle.EPMCFG] [tid: 65] [ecid: 7eeb9fd7-2d0f-4d3f-a525-322664eb6983-00000006,0:2:3:3:3:4:3:2] [SRC_CLASS: com.hyperion.avalanche.config.DocRepHubRegistration] Error registering instance file: Product not found.
...
[2020-01-02T16:23:04.706+00:00] [EPMCFG] [ERROR] [EPMCFG-07164] [oracle.EPMCFG] [tid: 65] [ecid: 7eeb9fd7-2d0f-4d3f-a525-322664eb6983-00000006,0:2:3:3:3:4:3:2] [SRC_CLASS: com.hyperion.avalanche.config.DocRepHubRegistration] Exception generated when calling CSS API: EPMCSS-20570: Failed to provision identity native://DN=cn=911,ou=People,dc=css,dc=hyperion,dc=com?USER. Application DOCREP:DocRepApp not found in system. Provide valid application id to provision user/group.
...

The issue here is that the application was created in the Shared Services registry but it is not linked to the Default Application Group. This was validated by checking the HSS registry report:

The roles for the document repository did exist in HSS:

So all that was required was to use the epmsys_registry utility to link the application to the project, using the project's object ID:

cd /d e:\Oracle\Middleware\user_projects\FND1\bin

epmsys_registry.bat createlink #e6811d83f677e6702c765b8316f6702f84S7ffb #DocRepApp.DOCREP

The validation that the link was successful can be taken from the HSS registry report:

After these changes the Explore button appeared in Workspace: