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One of my clients has saved many emails to Windows folders as text files without file extension, and now wishes to see previews of those files in Windows Explorer. I found a partial answer here to associate files without extensions so they will open with our desired program (notepad): How to set the default program for opening files without an extension in Windows? but those methods don't show the file content in Windows Explorer preview.

Any ideas?

posix
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4 Answers4

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According to all of above information, I have tested many times. we can rename the files without extension, no matter what other type of files you have in the folder.

  1. Run cmd.exe as administrator.
  2. Type CD C:\folderpath
  3. Type rename *. *.txt instead of * *.txt
  4. Now all the file without extension will become XXX.txt

If all the files has the extension, you will get The syntax of the command is incorrect.

enter image description here

Then you can use preview to see these files.

———————————————————————————————————————————— Update：

you can use the following command to rename all the files without extension in all subfolders.
for example:

CD:\abc   
for /r %d in (*.) do ren "%d" *.txt

enter image description here

Mokubai
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OOOO
  • 1,270
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Open the folder. Click on the empty area in address bar. Type cmd and press Enter. This should open the command prompt.

Type this command and confirm with Enter:

ren * *.txt

All files will have .txt appended to their names.

gronostaj
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Register a file type handler in the Windows registry for file extension "."

You will need administrator rights to do this.

Save the following snippet to view_extensionless.reg and double click the view_extensionless.reg file.

Accept all the warnings.

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT.]
"Content Type"="text/plain"
"PerceivedType"="text"
@="txtfile"


[HKEY_CLASSES_ROOT.\OpenWithProgids]
"VisualStudio.txt.10.0"=""


[HKEY_CLASSES_ROOT.\PersistentHandler]
@="{5e941d80-bf96-11cd-b579-08002b30bfeb}"


[HKEY_CLASSES_ROOT.\ShellNew]
"ItemName"=hex(2):40,00,25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,

  6f,00,74,00,25,00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,

  00,6e,00,6f,00,74,00,65,00,70,00,61,00,64,00,2e,00,65,00,78,00,65,00,2c,00,

  2d,00,34,00,37,00,30,00,00,00
"NullFile"=""

The "PerceivedType"="text" tells File Explorer to view it as text in the preview pane.

The rest allows you to double click the file and view it in notepad and also create a new extensionless file - it will appear as an additional New Text Document context menu item.

warren.sentient
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While the command line will do those things and sometimes that is what you need, the GUI program Advance Renamer will allow a lot more flexibility and selectivity.

gentisle
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