Find Duplicates - Search Options

 
This option limits the file types that the program considers when searching for duplicates. For example, to search for duplicate audio files only, choose the Audio file type.

The choices are:

•All File Types

•Application

•Audio

•Document

•Image

•Text

•Video
 

Note:
The program uses a file's extension to determine the file type.  The extension must be in the System Registry (in HKEY_CLASSES_ROOT\SystemFileAssociations) and have its PerceivedType value set to the corresponding value (application, audio, document, image, text, video).  For example, here's a screenshot of the System Registry showing that the PerceivedType of a XML file is "document".

The software program that creates the files having a particular extension is ordinarily the one that registers the perceived type for the extension. Changing these settings might impact your system.
 

 
These options define what it means for two files to be duplicates of each other.  You may consider two files to be duplicates if they have the same name.  Another person whose needs differ from yours may consider two files to be the same if they have the same content, regardless of their names.  It really depends on the situation and what you are using this tool for.  Choose any combination of the following options:

•Names Match

•Sizes Match

•Last Modified Date/Times Match

•Contents Match

File timestamps can be a little unreliable to use as duplicate criteria due to how the different versions of Windows handle timestamps.  Two files can be identical yet have differing dates.  Don't put too much stock in differing timestamps. 

The program requires you to select either the Names Match or the Sizes Match criteria as an initial selection.  You can then add any of the other criteria.
 

 
You should not remove some files on your computer, even if they appear to be duplicates. These include System files, Hidden files, and files in the Windows folder hierarchy.  Removing any of these files can cause your system to become unstable or unusable.  FolderMatch's default behavior is to ignore these types of files when searching for duplicates.  You can override the program’s default behavior by deselecting these three options:

•Ignore System Files

•Ignore Hidden Files

•Ignore Files in Windows Folder Tree

Additional Ignore options include:

•Ignore Temporary Files

•Ignore Zero Byte Files

A Temporary file (or temp file) is a file created by a program to hold information temporarily. After the program is closed, it should delete the temporary file. But sometimes this does not happen. Microsoft Windows and Windows programs often create a TMP file as a temporary file. If a temp file is in use, you don't want to remove it.  If it's old and should have been removed but wasn't, it should be safe to remove it.

Zero Byte files are files whose size is zero bytes; they contain no contents.  These files do not concern most users since they are not taking up any hard disk space.  

FolderMatch automatically ignores two other groups of files: files in the Recycle Bin and files in the FM_DUPES folder.  You cannot change this behavior.
 

Press one of these buttons to bring up a window where you can enter files and folders to include or exclude from the search. For files, you may enter a complete file name, like "thumbs.db" or you may enter a File Pattern using the wildcard characters * ?  like "*.dll".  For folders, enter the entire folder path or select a folder by clicking on the three dots .

Enter a file name or folder path and press the Add button to add the item to the list.  To remove an item from a list, select the item and press the Remove button.  To remove all items from a list, click on the Clear List link.

For a discussion of file patterns see the help file topic on Include/Exclude Filters.  Only the portion of that topic which deals with file patterns is applicable to the find duplicate files feature though.