Notes won't start - any solution that does NOT require deleting workspace?

On two separate occasions in the last month, I’ve had a situation where Notes 8.5 crashed and could not be restarted, even after killing all the processes.

The behaviour when I try to run it is that the splash screen appears, I successfully enter my password, then the progress bar creeps up to 100% and the splash screen disappears. The main Notes window doesn’t open.

The first time this happened, I followed instructions in another forum post and deleted the Notes workspace directory. This fixed the problem but I lost all my working sets in Designer.

So, is there a solution to this problem that does not involve deleting the entire workspace directory. I don’t want to have to create my working sets again.