Most error messages with severity level 16 reflect that the user has made a nonfatal mistake that does not fall into any of the other categories. Severity level 16 and higher can also indicate software or hardware errors.
For example, the user may have tried to update a view in a way that violates the restrictions. Another error that falls into this category is unqualified column names in a command that includes more than one table with that column name. Adaptive Server has no way to determine which one the user intends. Check the command syntax and working database context.
Messages that ordinarily have severities greater than 16 will show severity 16 when they are raised by dbcc checktable or dbcc checkalloc so that checks can continue to the next object. When you are running the dbcc utility, check the Error Messages and Troubleshooting Guide for information about error messages between 2500 and 2599 with a severity level of 16.
Levels
17 and 18 are usually not reported in the error log. Users should be
instructed to notify the System Administrator when level 17 and
18 errors occur.