Windows 10: renaming .mp4 to .gif breaks the file in question

simply put, renaming an .mp4 file to a .gif in file explorer breaks it, meaning it won't play or upload properly. however, renaming it back to mp4 causes it to work properly again. I've tried using different capitalizations with the target file format but no luck...it's almost as if windows started evolving backwards, starting from windows 8

:)

 

Renaming .mp4 files makes the unusable

I have some mp4 files that need renaming due to the name being not helpful. When I rename the file (not changing the file type) the file just doesn't work anymore.

For example: if I change the name from "91fg18o7.mp4" to "cats.mp4" the file won't play anymore.

Additionally:

1. the file would show a frame in the folder (viewing large icons) before rename, but after rename it would change to the icon of the default opening program.

2.- I have tried to open the file with VLC, Potplayer, etc. and nothing works.

3.- I use Windows 7 Pro.

4.- All the files were the problem has occurred are 4GB or larger.

5.- Undoing the rename doesn't help

So my question is: How to rename those files without breaking them? and if they do, how do you recover them?

Thanks in advance.

 

Renaming .mp4 files makes the unusable

Please post the complete text of the error message you get (if you get one) when you try to play one of these files.

Renaming a file -- even changing the file extension -- should not affect the content of the file.

As a test, I renamed a 5 GB mp4 file to have NO file extension. Although the file could not, of course, be opened used a double-click, it opened successfully either by using right-click > Open and selecting VLC player from the list or by first opening VLC
player and then dragging and dropping the file onto the open VLC window. This also worked if I renamed the file to have a txt file extension.

So ... exactly how did you go about renaming the file(s)?

Please post a screenshot of the folder showing the renamed file showing "the icon of the default opening program." After you open the folder in Windows Explorer, be sure that the box to "Hide extensions for known file types" is NOT checked in Tools > Folder
Options > View tab. Then right-click the file, select Properties, and post screenshots of the "General" and "Details" tabs.

What happens if you start VLC player (if it is in full-screen mode, press F11 to get it to windowed mode) and drag and drop one of your renamed files onto the VLC window? Please report the complete text of any error message.

 

USB doesn't display MP4 file!

I have a 300kb mix of .png, .jpg, .pdf files on a 4Gb USB drive. I added a 2Gb MP4 movie but it doesn't display in the drive files. I used CCleaner to check the drive F files .. it only shows up as 2Gb of OTHER FILES, but not in the listed files.

Any (constructive) suggestions welcome. I can't remove it as it doesn't show in the file list.