How do I figure out why opening a new window is slow? [OSX]


For some reason (a few updates ago), Atom now takes a few seconds to open a new window. It doesn’t matter if it’s an empty new window or a new window form a folder/directory, it just takes a bit of time.

Once the window is open, it just behaves normally. Counting externally it’s about 4 seconds to open a window. The console (developer tools thingy) says:

Window load time: 1125ms

It’s usually around 1100ms, yet the actual time it takes it three to four times that amount. It wasn’t always like that, and I don’t remember changing any setting, changing something in the package configuration or changing anything that might have something to do with Atom’s runtime behaviour.

Anyone have any clues as to how to figure this out?


Have you taken a look at the Time Cop View? It can be launched from the Command Palette.


It does show a different figure (1972ms). In the more specific list it shows a few slow loads such as:

  • Package loading:
    status-bar: 239ms

  • Package activation
    status-bar: 143ms
    snippets: 39ms
    release-notes: 27ms

in total there are 27 items that take ‘too long’ to load. (more than 5ms)
I’m running on a 2nd gen i5 and a Crucial SSD (M550) with 16GB of RAM, so it’s not likely a resource issue (I tested it with all other applications closed). Nothing else on my system seems to be affected.


FYI, under 2 seconds is a very good time for Atom to load.


Well, it does still open <2000ms, but when there is a window open, and I want to open a second window, that is what takes longer than it used to. It used to be somewhere between 200ms and 700ms, now it’s over 1100ms. The only change being an update. Maybe I should try to grab an older version to compare?


Found a weird difference:

  • Dragging a directory on to Atom causes a slow open
  • Using Terminal, “open . -a Atom”, fast open

I have no clue what the difference is from a technical perspective, but the result is definitely different.


Does the first one open a new window while the second doesn’t?


Both open in a new window. Atom is running with no open windows when both actions are performed.