The IndexMissing.log file contains information about items that have not been added into an index volume.  This document lists the possible reasons listed in the error column (the values listed after the last comma).  For more information about the function of the IndexMissing.log file, see technical article: How to read the contents of the IndexMissing.log file in the Related Documents section at the bottom of this article.

 -1 - Indexing failed to retrieve the item from storage
  0 - No reason available
  1 - Item has no content
  2 - Attribute value could not be obtained
  3 - Attribute value is (or appears to be) corrupt
  4 - Is not possible to convert attribute value to suitable format (i.e., no converter for this specific conversion)
  5 - Conversion of attribute value failed (i.e., converter error)
  6 - Conversion of attribute value timed out
  7 - Conversion excluded for this file type
  8 - Bypass conversion has been set
  9 - Attribute value is encrypted
10 - Attribute value requires conversion but converters are not available, or have not been initialized
11 - Unable to add attribute to index
12 - Converters did not recognize the file type
13 - Conversion excluded for large files
14 - Conversion excluded for code pages we cannot detect

Multiple values will be separated by a semicolon.  For example:

695010,201004020246464~201001212344150000~Z~E129CCEDDEA7D66713C63676F395D731,2;9;11

Note: Values other than -1 will only be logged into IndexMissing.log if the LogMissingItems registry key is set to 2 and the Indexing service is restarted to pick up these values.  More information about this registry key can be found in the Registry guide.

Warning: Incorrect use of the Windows registry editor may prevent the operating system from functioning properly. Great care should be taken when making changes to a Windows registry. Registry modifications should only be carried-out by persons experienced in the use of the registry editor application. It is recommended that a complete backup of the registry and workstation be made prior to making any registry changes.