This technote replaces a previous alert (ALERT2690) for DLP.
DLP systems upgraded to 15.5
The upgrade process to Data Loss Prevention 15.5 incorrectly applies a wild card replacement of .doc, .xls, and .ppt MIME types to Open XML MIME types.
This wild card replacement results in the following changes:
The additional MIME types for policy conditions can cause false negatives. They can also cause data loss for policy exceptions.
To address this issue, see the Knowledgebase article, "Red banner when editing some policies after upgrading to 15.5," and follow the workaround provided in the article.
The issue is fixed in 15.5 MP1.