This article was been published more than a year ago. The information may be outdated.
As I have noted earlier, Lotus Notes is not famous for having easily understandable error-messages, quite the opposite in fact. However, when you think a bit about it; some messages are clearer than others. An example of this is the “Invalid or non-existent document” error.
The problem in this case is that an entry in an NSF-file (a document in a database) is corrupt. This can happen for various reasons. There are two ways to fix the problem, one server-side, and one client-side.
On the server console, run the command
load fixup %NAME OF DATABASE%
This will remove the faulting documents from the index and from the database
Some databases can be replaced client-side (basically any databases located in the Data catalog of Notes). To replace them, simply rename the file, then start Notes. Notes will then recreate the file from the .ntf. NOTE: This will delete any and all entries in the database.