How to really, really re-assign file extensions to new application?


Extraordinary Member
At first an important request: Please read my problem carefully.
The solution is not as easy at it seems to be at the first glance!

Since WinXP I have a problem when I want to re-assign a file extension to another
application (=the program which should be used when double clicking on a certain file in WinExplorer).
This problem appears particularly when the old, current application is NOT existing any more!

Assume the following step-by-step simplified sample scenario:

1.) File extension *.avi is assigned to the well known videoplayer VLC in

2.) Now I extract another PORTABLE videoplayer foobarplayer.exe into

3.) I delete the vlc player directory

Ok, I admit it would be better to officially uninstall it. But the problem shouldn't exists here anyway.

4.) Now I want to re-assign *.avi extension to the new player. Therefore I right click in WinExplorer on an *.avi
program and select

Open With->Choose default program->Browse

I navigate to the new program foobarplayer.exe and click OK.

Surprisingly the OpenWith dialog still marks the old videoplayer program vlc or NO program. Even worse: The
new program is oftentimes not visible in this dialog. This drives me crazy.

It seems that internally Win7 still has Registry settings linked to the old default program which CANNOT be
OVERWRITTEN (by this way). The official often recommended re-assigning does NOT work.

I tried to find another way without luck. It seems to me that direct hacking the Registry is the only way.
Can this be real? I cannot believe that WinOS do not offer a real smarter enforced overwrite of file extension associations.

There are older programs as "assoc" and "ftype" which help me to do the job. But they are almost as uncomfortable as editing the Registry directly. This problem is NOT porgram specific but happened with a couple of programs in the past.

Probably it is because of the two-step association which cannot be handled by this way:


So again is there a real easy way/tool of re-assigning file extension to new programs regardless of what crap stuff is currently existing in Registry for that file extension?

Thank you

Last edited:


Honorable Member
First, when you choose a program to associate a file with it, you must be in the file association window and click "Always open this file with this program" (something like that). If you just choose "Open With"... that's a one time thing.

Do this:

1. Open the "Start" button and click the "Default Programs" shortcut. Click the "Set Associations" option.
2. Scroll down the list to find the file extension you want to change. Click it to select it.
3. Click the "Change program" button. Click the program you want to use to open the file. If the program doesn't appear, click the "Browse" button to find it. Click "OK" to set the file association.


Microsoft MVP
Staff member
Premium Supporter
Microsoft MVP
You might find it helpful to first run something like Ccleaner to clean up your registry - removing any setting no longer used for vlc. If that doesn't solve it I'd also run regedit and manually search for any occurrences of "vlc" and remove them.


Excellent Member
Microsoft Community Contributor
Just wondering if the D: locations were included in your path system variables.


Essential Member
Microsoft Community Contributor

You should use Revo Uninstaller to remove the software from your computer when you stopped using it.
Windows isn't good at getting rid of old registry entries at best but not uninstalling the software is a least part of your problem.

Revo will remove the left over registry entries when it does the uninstall so Windows won't think that the program is still there.

Just deleting it is always going to leave stuff behind.


Here's the link...

Revo Uninstaller -

Last edited:
This website is not affiliated, owned, or endorsed by Microsoft Corporation. It is a member of the Microsoft Partner Program.