Since many versions of MacOS, I got different applications leaving a ghost version only visible at the Finder and Dock level but not at the basic Unix level. Here is the usual error message the Finder does display when trying to start such a ghost application:
Activity Monitor doesn't show any
Preview process, and moreover
the Unix command
# ps ax | egrep '[ /](PID|Preview)' PID TT STAT TIME COMMAND #
Next, the Dock does display a small dot near the application icon, but refuse to force quit the ghost application.
Tested and failing solutions
The usual receipe ⌘+⌥+escfrom the Finder doesn't permit to force quit the ghost application.
Many not tested ( by their authors ) receipes talk of removing preferences files, but since these files are only open by the running application, this advice can only lead to a waste of time and a loss of working preferences. Killing the Finder or the Dock is possible but doesn’t fix the bad vision of the ghost application.
The MacOS cannot shutdown through the Finder menu entry:
> Shut Down... since the Finder cannot get rid of the ghost application
it sees as running when it isn't, here
On the other hand, a very basic Unix command permit to get a clean and fast shutdown, since at the Unix level there isn't any application impossible to kill:
/usr/bin/sudo shutdown -h now 'Finder see ghost applications'
Spread of the problem
From my experience this problem is concerning Yosemite and High Sierra. If you had the same problem on any more recent version of MacOS, could you signal it within the comments.
Versions of MacOS exhibiting the problem:
- El Capitan
- High Sierra
- Big Sur
Applications exhibiting the problem:
From what I read in different discussion groups, it looks like any application might reach this state of ghost for the Finder and the Dock. It is a very large spectrum problem, and Apple doesn't look to have figured it and doesn't provide any decent workaround or solution ( but the stupid and huge waste of time: reinstall MacOS. Stupid because you can't give such an advice when you don't understand a problem. )
The application seen as a ghost by the Finder is not the origin of the problem and none of its preference files. A simple demonstration can be obtained by starting it without the Finder:
Terminal simply enter for example:
$ open -n -a Preview.app $
and you will get a fresh new
Preview running with all its usual preferences and functions available. This new version will get a new icon within the
Analysis of the problem
Since I didn't find any decent explanation of this problem and no clean fix
of it I started my own investigation with the help of the
truss command which traces every key event within a Unix process running.
First I tried in a Terminal window:
$ /usr/bin/sudo dtruss -W Preview
and on another Terminal Window I tried to start Preview through:
$ open -a Preview.app LSOpenURLsWithRole() failed for the application /Applications/Preview.app with error -600. $
but nothing appeared within the
dtruss track, meaning that Preview didn't even start and of course none of its preference files were opened.
How to furter invistigate this large spectrum bug
My state of understanding of the problem is that there is a false view of the processes running on MacOS from the Finder and the Dock.
What may lead to this corrupted image of the processes on the system?
Which tools would be the best suited to further investigate this bug?
Where could I find any documentation about this
the meaning of its error codes?