Certain PowerPoint files containing embedded Excel spreadsheet content are called unscannable with Scan engine error code 0xA even though these files can be opened in PowerPoint without error.
The Windows Application Event Log shows the following error event:
Event ID 218
Source: Symantec Mail Security for Microsoft Exchange
The attachment "<file name>.ppt" located in message with subject "<message subject>", located in <location> has violated the following policy settings:
Rule: Unscannable File Rule
The following actions were taken on it:
The attachment "<file name>.ppt" was Quarantined for the following reason(s):
Scan Engine Error. CSAPI DEC result: 0xA. A malformed container is detected. at location Package within PowerPoint Document
Prior to performing these steps save the file to the filesystem from Quarantine. The file is saved to <install dir>\Symantec\SMSMSE\<version>\Server\Quarantine\Release.
The file is being saved as a 2003 ppt file, but contains some content that is native to 2007 pptx files. When SMSMSE uses the appropriate algorithm to decompose 2003 ppt files but then encounters content native to 2007 pptx files, it declares the file malformed.
Upgrade to 6.5.5 or later to resolve this problem.
Save the file as a PowerPoint 2007 document (*.pptx) before sending it through email.