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How to remove extensions (file type) association in Windows 10?

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Wednesday, September 2, 2015 5:38 PM | 1 vote

How can I remove extension association in Windows 10? Ihave tried assocc command but it is useless because it is saying that there is no association for this particular extension I want to make completely diassociated.

All replies (18)

Saturday, September 19, 2015 11:01 PM ✅Answered

Looks like W10 has made the usability even worse.

Using the tip found here for W8

http://superuser.com/questions/707196/how-to-remove-file-association-in-windows-8

I have managed to get Set Associations showing BLORT.BLORT as the current default.  Just giving it BLORT was not acceptable.  Open with... evidently wants something with a dot in it.   Now instead of opening the .HAR thing in Notepad I see  "THIS APP CAN'T RUN ON YOUR PC."  (very emphatic it was about that.)  

Before that I had associated it with SysInternals strings.exe program and made it the default.  All that accomplished was letting me see that there were two possibilities for Open with...  BLORT.BLORT is not listed there but is now the default.  Wonderful.  I'd love to see the Use-case analysis that allowed this scenario (and still managed to not allow anything useful.)

Oops.  I didn't complete the suggested steps.  I neglected to rename BLORT.BLORT to BLORT so now when I try to open a .HAR file I do get the How do you want to open this file? prompt.  I guess that's the answer.

Robert Aldwinckle

Friday, October 2, 2015 5:23 PM ✅Answered | 1 vote

I have solved my problem, finally. I have listed all registry for “notepad” and deleted those keys or folders where notepad.exe was associated with .class extension.

Thank you for your helping.

Thursday, September 3, 2015 4:36 AM

On Wed, 2 Sep 2015 17:38:21 +0000, Uzivatel 919 wrote:

How can I remove extension association in Windows 10? Ihave tried *assocc*command but it is useless because it is saying that there is no association for this particular extension I want to make completely diassociated.

What file extension are you referring to? If you run assoc with no
arguments does it actually show a current association?

Paul Adare - Directory Services (MIM CM) MVP
If my post answers your question, please mark it as an answer. I really
don't care about the points, marking it as an answer may help someone else
with the same problem. Thanks!

Thursday, September 10, 2015 2:44 PM | 3 votes

Hi,

How about remove the related .extension (the one you would like to remove associations completely) registry keys under following registry key folder?

HKEY_CLASSES_ROOT

HKEY_CURRENT_USER\SOFTWARE\Classes

Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

Thursday, September 10, 2015 5:57 PM | 1 vote

How can I remove extension association in Windows 10?

I agree with the other comments about assoc but think you should also check under Default Programs because it seems that there is now a lot of stuff in there which does not get reported by either assoc or ftype.

E.g. compare:   Control Panel\Programs\Default Programs\Set Associations

C:\WINDOWS\system32>assoc | find /i "zune"

C:\WINDOWS\system32>ftype | find /i "zune"

For more examples try just .z and z alone.

Also, note that the Set Associations list is a 2 part list and it is not searchable; so you must scroll through it to find the top and bottom of all its ranges.

 

FYI

Robert Aldwinckle

Sunday, September 13, 2015 1:28 PM

How can I remove extension association in Windows 10?

I agree with the other comments about assoc but think you should also check under Default Programs because it seems that there is now a lot of stuff in there which does not get reported by either assoc or ftype.

E.g. compare:   Control Panel\Programs\Default Programs\Set Associations

C:\WINDOWS\system32>assoc | find /i "zune"

C:\WINDOWS\system32>ftype | find /i "zune"

For more examples try just .z and z alone.

Also, note that the Set Associations list is a 2 part list and it is not searchable; so you must scroll through it to find the top and bottom of all its ranges.

 

FYI

Robert Aldwinckle

I have tried ftype command but my extensions is also not listed here.

Sunday, September 13, 2015 1:29 PM

On Wed, 2 Sep 2015 17:38:21 +0000, Uzivatel 919 wrote:

How can I remove extension association in Windows 10? Ihave tried *assocc*command but it is useless because it is saying that there is no association for this particular extension I want to make completely diassociated.

What file extension are you referring to? If you run assoc with no
arguments does it actually show a current association?

Paul Adare - Directory Services (MIM CM) MVP
If my post answers your question, please mark it as an answer. I really
don't care about the points, marking it as an answer may help someone else
with the same problem. Thanks!

I think your idea is the right one. The extension is no listed by the stand-alone executed assoc command.

Sunday, September 13, 2015 1:35 PM

Hi,

How about remove the related .extension (the one you would like to remove associations completely) registry keys under following registry key folder?

HKEY_CLASSES_ROOT

HKEY_CURRENT_USER\SOFTWARE\Classes

Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

                            

I have already listed all the registry by find function for this extension before I posted this question but the association as I know it from the past or from other extensions, I haven't found.

But I will have a look one more time for sure at locations you have mentioned.

Sunday, September 13, 2015 1:38 PM

Hi,

How about remove the related .extension (the one you would like to remove associations completely) registry keys under following registry key folder?

HKEY_CLASSES_ROOT

HKEY_CURRENT_USER\SOFTWARE\Classes

Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

                            

I have already listed all the registry by find function for this extension before I posted this question but the association as I know it from the past or from other extensions, I haven't found.

But I will have a look one more time for sure at locations you have mentioned.

I have had a look but this extension has got only one default key a no other subdirectories at both locations.

Sunday, September 13, 2015 4:06 PM

E.g. compare:   Control Panel\Programs\Default Programs\Set Associations

I have tried ftype command but my extensions is also not listed here.

So?  What do you see in the Control Panel's presentation?

BTW "extension abbreviations" are often not included in File Type names, so no surprise that you might not see yours listed there.

Robert Aldwinckle

Saturday, September 19, 2015 5:44 PM

E.g. compare:   Control Panel\Programs\Default Programs\Set Associations

I have tried ftype command but my extensions is also not listed here.

So?  What do you see in the Control Panel's presentation?

BTW "extension abbreviations" are often not included in File Type names, so no surprise that you might not see yours listed there.

Robert Aldwinckle

I see my extensions associated with Notepad. My extensions is .class (Java class file).

Saturday, September 19, 2015 7:45 PM

I see my extensions associated with Notepad. My extensions is .class (Java class file).

That's a great example of how horribly unusable these new undocumented "discoverable" UX can be. 

FWIW I just found that I had apparently associated HAR files with Notepad, so I decided as a test for this incident to get rid of that.  The UI suggests that it would let me disassociate it from Notepad provided that the Store knew about it.  Well, evidently the Store doesn't know about it and there is no obvious way to switch it from an association with Notepad to Unknown.  Unknown appears to be the association that represents files with extensions that exist but are not associated with a program.  Sort Default Programs\Set Associations by Current Default to see that there are lots of those.  There is nothing in the UI which allows us to either associate an extension with that Unknown class or delete one.  (I remember now making observations about these deficiencies before during a preview.)

So, for a workaround for this deficiency it looks like my only hope would be to create something using another method, hope that that collides with whatever the GUI is using, then delete it with a non-GUI method and hope that that produces an Unknown association in the GUI?  Or just hack the registry as some have already suggested.

Ugh.  I need to find a better example.  HAR matches common words such as Hardware and Share so it won't be practical to try to find all the implementation details in the registry for it.

And I have one!  It looks like it was created by IE Developer Tools.  I probably used Notepad to inspect it and didn't notice that I was creating an association and filetype at the same time.  Maybe deleting it or renaming its extension will change that association.  Who knows?  I'll try playing with this some more later.  I am interested in knowing if there is a better solution than hacking the registry, regardless of how quirky it may be.

Robert Aldwinckle

Saturday, August 19, 2017 3:12 AM

This might sound too simple, but because extension associations are registry entries, the easiest way might be to simply restore the registry to an earlier date through "Control Panel", "Recovery", "Advance Recovery Tools", "Open System Restore", and then select an earlier restore point or date to resort from.  If problems exist in in the restore operation, try starting up in safe mode before restoring.

Jim

Monday, November 6, 2017 12:03 PM

Could you guide me on the steps to achieve this please?

Wednesday, March 7, 2018 5:34 PM

I create a text file in my documents folder and named it bogus.bogus. It created it as bogus.bogus.txt. I renamed it to bogus.bogus. Then I went to Control Panel>Programs>Default Programs>Set Associations. (You may have to select Category View for Control Panel, initially.) I then associated bogus.bogus with the file type for I which I wanted the association removed. After making the association, I deleted bogus.bogus. The Current Default association is now listed as Unknown application. I have effectively removed the association.

Wednesday, May 16, 2018 6:56 AM

There's something missing from your procedure or the steps are out of order or something... or I'm an idiot  ".bogus" would not be listed in the Set Associations dialog unless you associated it to a program first, using File Explorer.  And how does deleting the file bogus.bogus affect the Default file association?

I'm trying to disassociate ".nps" from Notepad++, a file it uses rather than edits  How difficult would it have been for Microsoft to put "No app" in the Choose An App popup menu for a given extension?  Ugh.

Monday, May 21, 2018 11:39 AM

One possible strategy is making the OS open the dialog used to select the application to work with the specific type.

I commented the wrong application's .exe file associated with the file extension (.rar in my case) and tried to open a .rar file. This resulted in the default dialog opened - I was able to select the right program this time.

The commented .exe was returned to the default state then.

P.S. Yes, the UX of Windows 10 is a real pain in some cases. For example, why wouldn't it just allow to remove the extension in the Control Panel and not just suggest visiting the Store?

Tuesday, April 23, 2019 10:14 AM

start right click -> system -> find a setting "Choose a default app for each type of file" scroll to the extension of interest and change it to whatever you want