What is a .dead file for?

Question

When I uninstall some apps, they leave behind their install directory along with .dead file. It seems like it's specific to Electron/Squirrel applications. Slack is a prime example.

What's the point of this file? What purpose does it serve? Shouldn't an application remove itself entirely when uninstalled aside from user data?

Solution

.dead file seems to be created when you uninstall a squirrel app: https://github.com/Squirrel/Squirrel.Windows/issues/943#issuecomment-338869343

Update 26-06-2020. Moved from my comment to the answer, as requested. The purpose of the file as described in the link above:

Squirrel is adding the file to indicate the app is uninstalled, but it couldn't delete the directory. The FullUninstall method will not work on a folder with .dead file and the clean algorithm (that runs on pc startup) will skip these folders. From the code: "NB: If we cannot clean up a directory, we need to make sure that anyone finding it later won't attempt to run Squirrel events on it. We'll mark it with a .dead file"

Comments

[dapperdan1985]

"What's the point of this file? What purpose does it serve? Shouldn't an application remove itself entirely when uninstalled aside from user data?"

[Denxorz]

Squirrel is adding the file to indicate the app is uninstalled, but it couldn't delete the directory. The FullUninstall method will not work on a folder with .dead file and the clean algorithm (that runs on pc startup) will skip these folders. From the code: "NB: If we cannot clean up a directory, we need to make sure that anyone finding it later won't attempt to run Squirrel events on it. We'll mark it with a .dead file"

[dapperdan1985]

Can you include your last comment as part of your answer? It serves to answer the second paragraph in my original question. I attempted to edit the answer on my own, but the reviewer it was assigned to rejected it. I assume they didn't see the 2nd paragraph in my question because they rejected it on the basis that "This edit deviates from the original intent of the post. Even edits that must make drastic changes should strive to preserve the goals of the post's owner." As the OP, I don't feel that the answer as it is now satisfies the question without the comment. They work together.

[Denxorz]

@dapperdan1985, it is relevant to your question indeed. Moved it to the answer as well.

[user1846903]

I have also seen it with other installers, e.g. in the MicrosoftTeamsMeetingAddin subdirectory.

[Denxorz]

@bernard Microsoft Teams also includes Squirrel.exe, so I assume it uses Squirrel. Hence, it can create .dead files when uninstalled.

[Qwerty]

I don't understand. If the clean algorithm skips folders with .dead file, why put it there?