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Forefront fore SharePoint Exchange Compressed File Size settings

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I get these issues every few months.

SharePoint or Exchange Admin getting files deleted due to Large uncompressed size or large compressed size virus.

We have a few KB’s on this but there is some detail that is missing.  I also realized today that the keys documented in KB 972072 are missing another file size setting.

 

Forefront for SharePoint / Exchange has 3 file size settings that restrict compressed file uploads.

 

Compressed means any container file, For example: Office 2007+ documents are compressed and would be subject to these settings.

Proactively you would want to set these keys to reflect the file size limits in your environment.

 

The compressed file limits are as follows.

Compressed file size: This is the total size of the file you are uploading. By default this is set to 25mb.

Uncompressed Size: This is the total size of ALL the files once extracted. This is set by default to 100mb

Uncompressed File Size: This is the size limit for any 1 file in the compressed file.  This is set by default to 20mb.

 

So you could have a 24mb xlsx file that extracts to 90mb, but if one file in that document is 21mb, it will trigger the file size limit.

Here the keys responsible for these files in SharePoint. In exchange it would be in the Forefront for exchange Key in HKLM\Software.

 

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Forefront Server Security\SharePoint

or

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Forefront Server Security\SharePoint

 

 

MaxUncompressedFileSize – Default is 100mb in bytes

MaxCompressedSize  - Default is 26mb in bytes

MaxCompressedArchivedFileSize – Default is 20mb in bytes

 

You would want to set these keys to reflect the file size limits in your environment

If your upload limits are set to 50mb you would want to set the maxcompressed file size to at least 52428800 (Decimal)

You would expect those files to be over 100mb uncompressed so you should set MaxUncompressedFileSize at 209715200 (200mb) or more.

And you can increase the MaxCompressedArchivedFileSize to 52428800 as well.