I thought of something else: what are the names of bad-connecting databases? I had a case when the server name contained a dash - and I had to enclose the name in [] for the name to work. Same may be applicable to the database names based on the provider you use for the linked server. Check for spaces in database names. Also check that you spelled the database names correctly. And one more thing: make sure you are connecting to the correct server that contains these databases. No, it is not a joke, it does happen.