Hi Nathan,
Please can I suggest that you download Bentley Configuration Explorer and run it on your system.
Once installed, click on Home tab > Process Configuration.
Pick the appropriate Application, user and Project, then click Process.
Once the process has completed the number of files, variables, etc will be displayed.
Click the Save icon in the quick access toolbar at the top right, save the Workspace File (.bcf) and send it as an attachment to this SR.
We can then load it into configuration explorer here and review your configuration, this should help us to give you some more specific advice about how your system is set up.
Do you see any errors in the message center when starting ABD or opening files? If so please see The Message Center - Some Tips and follow the advice given to increase the number of messages listed and how to save messages. Any relevant messages can also be attached to this SR (or a reply e-mail).