Sighing… about your first sentence. I don’t like that either, at least limit to only tags but not compulsory. It often takes me more time to find the tags than writing the blog when I post a blog.

That error message is – sadly –  a ‘fit for many’ errors. Although it does mention several possible causes, those are not the only ones. It could be that the developer who created the project didn’t quit it correctly and lock files (extension lck) are still on his system.  But many other reasons are possible.

Check if you have the backup file and are able to open that file? Clean the Preferences (to solve eventual corruption of that folder). Use the CleanPreferences… file to run, which you find under ‘utils’ subfolder under the installation folder (Captivate needs to be closed and you need admin rights).