Cannot set a Windows 10 Store App as default program to open a file

The store app has to make the registration in this registry key:

HKEY_CURRENT_USER\SOFTWARE\RegisteredApplications

And then set the File association\Capabilities in another key, mentioning each file type it can handle. For example Microsoft Edge has the registration here.

HKEY_CURRENT_USER\SOFTWARE\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\AppModel\Repository\Packages\Microsoft.MicrosoftEdge_25.10586.0.0_neutral__8wekyb3d8bbwe\MicrosoftEdge\Capabilities\FileAssociations

If you can post the export of RegisteredApplications branch, I can make a REG file which adds the FileAssociations info for that application.

With this done, the application should be normally displayed in the Open with.. dialog, as well as in Default Apps.

Update (May 3 2016):

You can use this REG file to add .CONF file type, using the same association setting for CodeWriter .txt file type.

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\SOFTWARE\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\AppModel\Repository\Packages\ActiproSoftwareLLC.562882FEEB491_2.5.17.17_neutral__24pqs290vpjk0\App\Capabilities\FileAssociations]
".conf"="AppXea46y3k4tynme684q1dgefbnb0b9r8ec"

Pls note that you need to take ownership of the above registry key, add yourself full Permissions, then merge the REG file. Once done, reverse the Permissions to defaults.

Note: This REG file is valid for the current version (as of this post) of Code Writer. If you have any other version, make the modification in the appropriate key.

The key might have the following naming/numbering convention or similar.

ActiproSoftwareLLC.562882FEEB491_n.n.nn.nn_neutral__24pqs290vpjk0

Easier way:

1. If you know windows already has a default or it is common enough that it is recognized, skip to step 2. Otherwise, assign it a default manually (just pick a random app - it doesn't matter).

2. Open settings, go to "apps" on the left, default apps

3. Click on choose default apps by file type (it will be a link in your accent color).

4. Find the file type you want it to open with - I couldn't find .conf by default but I assigned it to Notepad and then I found it.

5. Click the app it is currently assigned to and select choose an app in the Microsoft store.

6. Find the app you want to use. You most likely have it installed but if you don't, do it now. Done!