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Attachments sent from Apple Outlook from MAC are blocked by ScanMail for Exchange (SMEX)

    • Updated:
    • 25 Mar 2019
    • Product/Version:
    • ScanMail for Exchange 10.2
    • ScanMail for Exchange 11.0
    • ScanMail for Exchange 12.0
    • ScanMail for Exchange 12.5
    • ScanMail for Exchange 14.0
    • Worry-Free Business Security Standard/Advanced 7.0
    • Worry-Free Business Security Standard/Advanced 8.0
    • Worry-Free Business Security Standard/Advanced 9.0
    • Platform:
    • Windows 2003 Enterprise
    • Windows 2003 Standard
    • Windows 2008 Enterprise
    • Windows 2008 Standard

You frequently experience SMEX blocking attachments that are sent from Apple Outlook for MAC. This issue happens for some attachments such as .jpg files.

The SMEX_Master.log below shows an example where L386040S.jpg is the attachment blocked by SMEX.

2012/09/14 10:38:00 +0200 [3228 : 5820] [filterattachmentblocking.dll][abf_AttachmentBlockingFilter.cpp( 795)] [DEBUG] ==> CABFAttachmentBlockingFilter::IsBlockedContent(vsc = 529397e0, ptmvsVsapi = 0x00000000234ED310, wstrAttachmentFilename = "L386040S.jpg", pvContent = 0x000000002361DE80, unContentSize = 69632, pcfgFileBlocking = 0x0000000023E1BF40) 2012/09/14 10:38:00 +0200 [3228 : 5820] [filterattachmentblocking.dll][abf_AttachmentBlockingFilter.cpp(1371)] [DEBUG] ==> CABFAttachmentBlockingFilter::GetFileExtensionByName(strFilename = "L386040S.jpg"), chExtensionSymbol = '.'
2012/09/14 10:38:00 +0200 [3228 : 5820] [filterattachmentblocking.dll][abf_AttachmentBlockingFilter.cpp(1385)] [DEBUG] <== CABFAttachmentBlockingFilter::GetFileExtensionByName(strExt = "jpg"), bResult = true 2012/09/14 10:38:00 +0200 [3228 : 5820] [filterattachmentblocking.dll][abf_AttachmentBlockingFilter.cpp( 875)] [DEBUG] pcfgFileBlocking->GetScanningType() = CCfgSettingFileBlocking::ST_SPECIFIED_SCAN 2012/09/14 10:38:00 +0200 [3228 : 5820] [filterattachmentblocking.dll][abf_AttachmentBlockingFilter.cpp(1688)] [DEBUG] Ok to call ptmvsVsapi->m_VSResourceDataType(vsc = 0x529397e0, pvContent = 0x000000002361DE80, unContentSize = 69632, dt.vsd_Type = 115, dt.vsd_SubType = 2, dt.vsd_TypeFlag = 32768, dt.vsd_TypeExtFlag = 0, dt.vsd_TypeName = "MacBinary-III") 2012/09/14 10:38:00 +0200 [3228 : 5820] [filterattachmentblocking.dll][abf_AttachmentBlockingFilter.cpp(1183)] [DEBUG] strFileTypeList contains "MACBIN"


The log above shows that the attachment is detected as TypeName = "MacBinary-III", which is an archived file format.

Because the Macintosh file (through Mac OS 9) contains two (2) parts, and telecommunication programs only send one part of the file, MacBinary can be used when binary files are placed on an FTP server or emailed through the Internet. It allows the various parts of a Macintosh file to be combined into a single chunk of data that can be sent anywhere and downloaded to any kind of computer. The file is then reconstructed into the original Macintosh file at the end of its journey.

MacBinary consists of 128 bytes, which are added at the beginning of the file. Most Macintosh telecommunication and Internet programs automatically use MacBinary when a binary file is sent. Some applications also allow MacBinary to be disabled. If you are sending a binary file (ie TIFF or JPEG files), to someone who uses a Windows computer, you must turn off MacBinary encoding. If you do not disable MacBinary encoding, the 128 bytes added at the beginning of the file will corrupt the file.

There are ways of removing the MacBinary information, but most of these are designed for Macintosh. At one time there were a couple of MS-DOS terminal programs that automatically detected MacBinary files and stripped off the first 128 bytes of the file.

To turn off MacBinary encoding, refer to the documentation by Apple, Mac OS X Server 10.2: How to Turn off Automatic MacBinary Encoding. The article helps you decide the best way to send your files through email systems.

If you are placing binary files such as applications, compressed binary files (StuffIt, Compactor), or other Macintosh specific binary files on a remote file server or FTP site, here is a chart that can help you determine if you need to use MacBinary or not:

Primary usersMacBinaryExamples
MacintoshYesApplications, Control Panels
MS-DOS/WindowsNoGIF, TIFF, QuickTime, MIDI files
MixtureNoGIF, TIFF, QuickTime, MIDI files

The attachments should be treated as .jpg format by SMEX after disabling MacBinary.

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