If a printer share is no longer available, and your event log contains:

                                 Event ID: 19                                 Source: Print                                 Type: Error                                 Category: None                                 Description: Sharing printer failed, \<print share name>.
it could be that you were over zealous in documenting the printer and included more than 256 characters in the comment field.

Reduce the size of the comment to less than 256 characters and restart your computer.