I had a hard time as I misconfigured “umask” setting on macOS.
So, I want to leave a note.

It was happened about 1 month after I setup “umask” on my Mac.
I didn’t understand what is happening as I already forgot about that.

1st error

I saw the 1st error when I updated Slack.app on AppStore.

Library not loaded: @rpath/libffmpeg.dylib

It says, I felt, one of the required libs:

• was deleted; or
• was not included when bundle the app;

Nothing tell me about misconfiguration of “umask”

I found an GigHub ISSUE on Signal Desktop.

As both of Slack and Signal Desktop are using Electron,
I suspect the Electron framework might be the cause.

I Googled, but I couldn’t find any related information about that.

I, still, could use Slack.app if I install it from web without AppStore. So, I leave the error at that time.

Real cause of this error

More time passed, and, more apps suffered this error.
And not only apps using Electron.

I also found:

• some processes are not responding; and
• cannot open “Security & Privacy” pane on Setting.app;
• /Application directory freeze Finder.app;

Why, why, why??

Hints from Console.app’s log

So, I checked Console.app, and I found a lot of Permission denied errors.
I fixed those errors by fixing permission of files.

And also found logs like following

fault	00:00:00.000000+0000	sysextd	bad ownership/permissions on sysextd staging area

And I remember that “I set up umask before!!”

Solution

Execute the following command & restart, and fix broken permission using chmod.

sudo launchctl config system umask 022

Or, delete UMASK section from plist

/private/var/db/com.apple.xpc.launchd/config/system.plist

We should be super careful when change umask on macOS, as described here.