Excluding: & Max size Mb:
Excluding:
Construct a list of file extensions and file path and file name phrases that you do not want shadowed. Windows applications often create temporary work files which this feature is designed to filter out.  
You can use the * wildcard for file extensions but it is not required for file path and file name phrases.

Examples of file extension exclusions:
.~*
.tmp
.bak

Examples of file path and file name phrase exclusions
\temp\      (will exclude all files with "\temp\" somewhere in the file path)
\temp       (will exclude all files with "\temp" somewhere in the file path and name)
File phrase exclusions are particularly useful if you have temporary folders that you don't want to shadow included within your folder structure.

Exclusions normally only apply to shadow specification lines which use the *.* wildcard eg.
c:\My Documents\*.*  /s    
If you need to override the exclusions then use the following:
c:\My Documents\*.tmp  /s      /rem explicitly stated extensions are not excluded
c:\My Documents\*  /s              /rem the * wildcard (instead of *.*) ignores exclusions and shadows all files.

If you need to exclude a particular file extension or phrase completely then suffix it with /x+
For example:
.tmp  /x+   will exclude .tmp files from being shadowed by all spec lines except those explicitly stating the file extension such as c:\My Documents\Readme.tmp and c:\My Documents\*.tmp

You can also add exclusions to the main 'Files to shadow' specification using the /x control switch. This feature is particularly useful if you need to restrict the scope of the exclusion to a named removable volume by combining the /x and /n control switches. 

Max size Mb:
To prevent large files from being shadowed use the Max size Mb field and check box.
For example, to prevent files larger than 1.4 megabytes from being shadowed, enter 1.4 in the Max size Mb field and make sure that the check box is checked. Your change will be validated and you will be advised of any files that have been excluded.  If you uncheck the check box then the large files will be shadowed at the next run. 
You can override this default maximum size on individual lines by using the /m control switch.
For example 
c:\My Documents\*.*  /s  /m=3  /rem will not include any files > 3Mb 

Note that the /m control switch does not use the default Max size Mb field's check box.