After opening an incident, CommVault provides a recommended solution which fixed my problem. I'll try and paste it below for future reference.
After upgrading to V11, the Commserve Console web application may open but not be responsive. Effects can vary but buttons and lists do not generate as expected. This is resolved by deleting the Java cache, steps seen here:
- Open Java in the Control Panel (See picture A)
- On the General Tab, select “Settings” (See picture B)
- Select “Delete Files”
- Ensure all 3 options are selected, and hit “OK” (See picture C)
Once this is done try logging into the Commserve Console as normally done. You will likely have to re-download the Java applet from the Commserve (or whatever machine is serving the console).