Update search-howto-index-sharepoint-online.md

Updated stating that encrypted content is not supported and how to find items that are causing encryption errors.

Author: gmndrg

articles/search/search-howto-index-sharepoint-online.md

@@ -9,7 +9,7 @@ ms.service: cognitive-search
 ms.custom:
   - ignite-2023
 ms.topic: how-to
-ms.date: 12/18/2023
+ms.date: 12/19/2023
 ---
 
 # Index data from SharePoint document libraries
@@ -60,6 +60,7 @@ Here are the limitations of this feature:
 
 + SharePoint supports a granular authorization model that determines per-user access at the document level. The indexer doesn't pull these permissions into the index, and Azure AI Search doesn't support document-level authorization. When a document is indexed from SharePoint into a search service, the content is available to anyone who has read access to the index. If you require document-level permissions, you should consider [security filters to trim results](search-security-trimming-for-azure-search-with-aad.md) and automate copying the permissions at a file level to a field in the index.
 
++ Indexing user-encrypted files, Information Rights Management (IRM) protected files, ZIP files with passwords or similar encrypted content isn't supported. For encrypted content to be processed, the user with proper permissions to the specific file must remove the encryption so the item can be indexed accordingly when the indexer runs the next scheduled iteration.
 
 Here are the considerations when using this feature:
 
@@ -476,6 +477,14 @@ You can also continue indexing if errors happen at any point of processing, eith
 }
 ```
 
+If a file on the SharePoint site has encryption enabled, an error message similar to the following may be encountered:
+ 
+```
+Code: resourceModified Message: The resource has changed since the caller last read it; usually an eTag mismatch Inner error: Code: irmEncryptFailedToFindProtector
+```
+
+The error message will also include the SharePoint site ID, drive ID, and drive item ID in the following pattern: `<sharepoint site id> :: <drive id> :: <drive item id>`. This information can be used to identify which item is failing on the SharePoint end. The user can then remove the encryption from the item to resolve the issue.
+
 ## See also
 
 + [Indexers in Azure AI Search](search-indexer-overview.md)