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I am attempting to set the default program to open a file with and I am unable to do so. I am using Windows 7 and the file extension I am attempting to set a default program to is bfa (*.bfa); the program that not only generates this file type but also the program which I am attempting to set as the default to open it is Blowfish Advanced CS (http://bfacs.sourceforge.net/).

When I right click a file and select "Open With", I go through the motions of trying to select the program: clicking "Browse" with "Always use the selected program..." checked and then I browse to the program. Once I select the program it fails to pop up as an option in the "Open With" dialog. I suspect the problem relates to the fact that the OS is 64-bit and application is 32-bit. Any suggestions on how to proceed?

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6 Answers 6


Control Panel\All Control Panel Items\Default Programs\Set Associations

enter image description here

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Thanks, I did try this; it ultimately will end up bringing up the same "Open With" dialog. When I tried it this way it failed as well. –  Gedalya Oct 7 '13 at 17:50
@Gedalya can you open the program directly and then the file within the program? and when you choose to open it with your program, what program if any does it try to open the file in? –  barlop Oct 7 '13 at 18:37
I can open it directly with my program. Currently the file is associated with Adobe Acrobat; this is by accident though. When I first installed the program the file type was unassociated; when I tried to associate it it was accidentally associated with Acrobat. –  Gedalya Oct 7 '13 at 18:58
so was acrobat always opening it? and you couldn't stop acrobat from opening it until you change the file association within blowfish itself? –  barlop Oct 7 '13 at 20:35
No, Acrobat wasn't always opening it. I associated the file with Acrobat on accident; I went through the motions of trying to associate Blowfish and didn't pay attention to the fact that it wouldn't let me and Acrobat was selected so it ended up being associated. Acrobat doesn't really have anything to do with the problem. –  Gedalya Oct 7 '13 at 21:41

I had the same problem, and none of the solutions worked (like the above method of going to the Control Panel - which does the same thing if you right click the file->Open With->Choose Default). Even after selecting the new program many times, it was stuck with the old one.

I fixed it by editing the registry. Go to the concerned extension like this (I had problem with .cpp):


Besides these two keys: OpenWithList and OpenWithProgids, it might have a third one called 'UserChoice'. Just delete that third key. After that, it will allow you to change the default program for that file extension.

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I had similiar problem, when I upgraded from Sublime Text 2 to Sublime Text 3. Navigate to Computer\HKEY_CLASSES_ROOT\Applications\ find the key for (application name) and just delete it. Then do the Open With (default=) trick again, and it all works. –  zipzit Nov 14 '14 at 23:40

I was able to fix my problem with the program itself. See the picture below for reference; under 'Tools' > 'Options'

The 'Miscellaneous' tab; under 'Registry Setup' there are two options that alter the registry. I applied both and it works now. What isn't clear is how I could have done this without the program doing this.

enter image description here

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you can accept your own answer –  barlop Oct 8 '13 at 21:48
The program was probably actively working against you. Every time it loaded and the 'Associate File Types' box was unchecked, it probably scrubbed the filetype association out of the registry. –  Brian Dec 31 '14 at 19:36

I had similiar problem, when I upgraded from Sublime Text 2 to Sublime Text 3. Navigate to Computer\HKEY_CLASSES_ROOT\Applications\ find the key for (application name) and just delete it. Then do the Open With (default=) trick again, and it all works. – zipzit Nov 14 at 23:40

This is close to the correct solution. Find the application key, lets say for Notepad++.exe in \HKEY_CLASSES_ROOT\Applications\notepad++.exe \shell\open\command\ Check the standard value of the registry if the .exe path is right. If not, then change the path to the correct one. After doing this, you can go to the file and use the standard way Open With and choose the program you wish to open.

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Just for you guys to know...

I had the same problem on win8.1.

That default file dialog seems to hang explorer, it happens both from the folder´s right click option and from set association screen, I think there is some problem with that functionality...

For me, killing explorer process via Task Manager and reopening explorer, (from task manager) via File -> new Task -> explorer.exe, completed the process of setting the default program normally and everything works fine now.

I don´t know if was just luck, but it is worth trying...

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i fixed this issue by right-clicking the file i wanted to open and choosing "properties". on the "general" tab it said "opens with: unknown program" or something like that. i just clicked the "change..." button next to that message and picked the app i origionally wanted. i think maybe this happens when the associated application gets deleted.

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