MS Edge (any channel build) reverts the within-sandbox file/protocol associations to MS Edge.Stable build when running sandboxed

[MuddyBleach]

Describe what you noticed and did

1. Have a version of MS Edge (Chromium-based) other than Edge.Stable installed on your PC. I personally am going to address Edge.Dev here below.
2. Make Edge.Dev your default browser. Make sure the same is for htm, html, pdf...-files and http, https... -protocols.
   3.Now you can select any htm, html, pdf-file and start it unsandboxed. It will open in Edge.Dev. Any time, predictably, irrespective of newer OS updates etc.
3. Create a new empty sandbox.
4. Select the same file and start it sandboxed. It will open in Edge.Dev. as expected.
5. Keep Edge running for a while, it may take a couple of minutes sometimes, until it does a check (?) and introduces changes.
6. Start the same file sandboxed for a second time. Now it will open in... Edge.Stable. Otherwise it will return an error in case Edge.Stable is not available on your PC (removed or blocked). The same is for http, https... -protocols. Sandboxed programs that need to open windows in external browsers either revert to that existing Edge.Stable or begin to show errors or do nothing where Edge.Stable is absent.

How often did you encounter it so far?

everytime

Affected program

Ms Edge, Chromium-based, any channel build

Download link

not relevant

Where is the program located?

The program is installed only outside the sandbox.

Expected behavior

File association should stay preserved, i.e. be the same as generally in the unsandboxed Windows.
Indeed, the most obvious move in that situation, when using alternative browsers, would be to avoid starting Edge in specific sandboxes at all. But the catch is that in that way alternative Edge channel builds would cancel themselves completely out since they get forced to reassociate their files with Edge.Stable again when running sandboxed and thereupon go almost impracticable.
So the links surprisingly open in Edge.Stable having different user profile, settings and per-build functionality as the default Edge browser or do not open at all as Edge.Stable not present and replaced, say, with Edge.Dev (which does not cause any single issue outside sandboxes)

What is your Windows edition and version?

Windows 10Pro 22H2, build 19045

In which Windows account you have this problem?

A local account (Standard user)., A local account (Administrator).

Please mention any installed security software

MS Defender

What version of Sandboxie are you running?

Sandboxie Plus 1.9.3

Is it a new installation of Sandboxie?

I recently did a new clean installation.

Is it a regression?

not sure about that

In which sandbox type you have this problem?

In a standard isolation sandbox (yellow sandbox icon).

Can you reproduce this problem on a new empty sandbox?

I can confirm it also on a new empty sandbox.

Did you previously enable some security policy settings outside Sandboxie?

No response

Crash dump

No response

Trace log

No response

Sandboxie.ini configuration

No response

[offhub]

For some reason the UserChoice subkey is being created in the sandbox registry even though it is present in the host registry.

Try with the following settings:

ReadKeyPath=HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\Shell\Associations\UrlAssociations\*\UserChoice
ReadKeyPath=HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.*\UserChoice

sbie-issue2949.mp4

[MuddyBleach]

Oh, thanks. These settings have worked out so far. But I assume they might prevent properlty associating other programs that are being installed inside the sandbox, so we will then need to disable them temporarily anyway.

[offhub]

You can assign rules to a specific program or program group.

msedge.exe:

ReadKeyPath=msedge.exe,HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\Shell\Associations\UrlAssociations\*\UserChoice\*
ReadKeyPath=msedge.exe,HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.*\UserChoice\*

chrome.exe:

ReadKeyPath=chrome.exe,HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\Shell\Associations\UrlAssociations\*\UserChoice\*
ReadKeyPath=chrome.exe,HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.*\UserChoice\*

Both:

ProcessGroup=<PreventDefault>,msedge.exe,chrome.exe
ReadKeyPath=<PreventDefault>,HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\Shell\Associations\UrlAssociations\*\UserChoice\*
ReadKeyPath=<PreventDefault>,HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.*\UserChoice\*