Error - 16: No such attribute

Created: 2012-04-20 08:09:59
Modified: 2024-02-07 15:09:55
Tags: Errors Troubleshooting UnitySync

When syncing to LDAP, all attribute mappings are controlled by the default or custom map file. In most cases, this error occurs if a mapping specifies an invalid Destination attribute name. The LDAP Add or Modify attempts to write this non-existent attribute, and throws an error as a result:

16: No such attribute

Unfortunately, AD/LDS error does NOT tell us which attribute it’s complaining about.

There is an easy (if slightly tedious) method to identify the attribute throwing the error.

A) Are you using a Custom Object Map file? If not, please create one as shown here.

B) Now comes the tedious part… One at a time, comment out a single attribute mapping.

(NOTE: Do NOT do this for the DN or objectclass mappings). Be careful to only make the desired change. Don’t edit anything else.

C). To comment an attribute mapping, insert the character # as the first character in the mapping line.

example: givenname#64=^givenname^

Add a leading # character to comment out the line


  1. If you already had a custom object map file, look for typos in the attribute names (on the left of the = character). If none jump out, continue on to find the problem attribute mapping by repeating these steps.
  2. Open the Custom object map file.
  3. Select the attribute to test and insert the # character.
  4. Click Save (the map file).
  5. Run your Sync.
  6. If the error does not occur, you’ve identified the attribute! That attribute is not in the destination schema.
  7. If the error still occurs, return to step 2. (Note: Remove the leading # character from the previously tested attribute).

For further assistance, contact

When syncing to an AD/Exchange 20xx Destination:

In addition to the above error summary, there is another known cause of this error that is specific to connections that sync to an Active Directory(AD)/Ex20xx Destination. The default map template for AD is ActiveDir-contact (mail enabled) . If you are using this default template and you get this error, it is likely that Ex20xx is not actually loaded on the Destination . Therefore, attempts to set Exchange attributes are causing this error because they do not exist on the Destination as is.

In this case, you must either load Ex20xx on the Destination, run Forest Prep, or create a new connection that creates simple AD Contacts that are not mail enabled.


When syncing to a Lotus Notes Destination:

In addition to the above error summary, there is another known cause of this error that is specific to connections that sync to a Notes Destination. If a Source object does not contain a primary mail attribute value, your initial sync to Add the Notes object will be successful. However, subsequent syncs that might try to Modify that object will fail with this error. The Modify will return this specific error:
16:Failed deleting item InternetAddress, item not found

Then the Sync summary will show the LDAP_NO_SUCH_ATTRIBUTE. In this case, it is recommended you use an Optional LDAP Query Filter (Source tab) to exclude Source objects that do not contain a mail value. You can do this by adding the following LDAP Query Filter:

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