Installed workflow designer on a new computer, after setting up the connection profile, I am still unable to select it from the Get metadata from drop-down menu.
You need to set a default connection profile in Tools\Options\General.
I had a system that would not start workflows, even though the subscriber evaluated to true. We usually setup the repository connection in the Workflow Configurator where you don't need an account. It asks you to enter credentials to be used one time, and says it will not store those credentials.
However I had to go to Tools > Options > General and create another connection here with permanent credentials before the workflows would start. As soon as I did this it went back and started all the workflows that were waiting.
That's unlikely to have been the fix. Connections set under Tools\Options\General are used for designing workflows. The server is not aware of their existence, nor does it check them to start workflows. Published workflows contain their connections as they were when the workflow was last published.
Makes sense as I never visited this config before and workflows always started. I assume the repository is accessed via the WFUser$ account created when you configure the repository.
I don't know why WFs were not starting as there was nothing posted to any error logs and the sub trace showed true for an entire starting condition rule that was active.
I tried everything until I hit this setting before it finally worked.