I can't kick off Infrastructure manager and I see that there are large queue file(s) under $NIMROOT\hub\q folder
This is general information applicable to most versions of UIM.
Check if $NIMROOT\hub\q directories have any large size queue file.
If so, and there is a hub process running, check the $NIMROOT\hub\hub.log file.
The file will contain entries for queue files that have been verified and are already attached.
It will also contain entries indicating that it is currently verifying the other queue files.
After the hub has done this queue file integrity check, it will start listening and accept connections.
In this scenario, you have to wait for the hub process to complete queue file verification.
This can take from a few minutes to a couple of hours depending on the size of the queue file and the available system resources.