I've just installed v. Workflow 2010 on our test system - version 188.8.131.52 (a little out of date, I know, but want to replicate the live system). I tried activating it in "Site collection features", in a newly-created site collection, and an "unexpected error" message was displayed in the browser.
Extracted the log lines for the given correlation ID, which included the following:
I've checked, and the feature.xml file is present (and apparently identical to the file on the live system). I've tried restarting the application pool, to no avail.
Has anyone seen this before, or any suggestions for further investigation?
Apologies, have just answered my own question.
Looked further down in the stack trace, and found this:
Nintex.Workflow.NWDatabaseConnectionException: Failed to open a connection to the Nintex Workflow configuration database. ---> System.InvalidOperationException: The ConnectionString property has not been initialized.
I'd omitted the stage of setting up the config database.