Sketch Mirror very slow

Hello there,

I’m very grateful for all the improvements Sketch has made over the last few years. We were especially relieved when Sketch Mirror was finally completely revamped and now reliability connects to the Mac app.

However it seems that the app was somehow overengineered, making it almost unusable as soon as your Sketch file becomes larger. It’s great that the app can download files from Sketch Cloud independently (I mostly see that feature as a last resort of “I really want to preview this thing and my Mac is not available”), but if all I want is to display artboards from my Mac to my phone, why does it need to download everything every time? My file is 120MB and it often takes 1-2 minutes to download and open and sync with the Mac state. Add on top of that that the app doesn’t prevent auto-lock, so often you just lose the state and everything needs to be redownloaded.

When in “Mirror Mode”, why isn’t the Mac app simply sending an image to the iOS app to display? Instead of the iOS app dealing with the entire Sketch file (and only receiving some artboard ID to display from the Mac app I presume).

1 Like

Hi Sam,

Thanks for sharing this report. I tested and I haven’t been able to reproduce the problem you mention. I tested with an 86MB (named Working file - January 2024) file and did the following:

  1. Opened it in the iPhone app
  2. Closed it and reopened
  3. Closed the app, reopened the file
  4. Locked the phone, reopened the file, didn’t lose my artboard
  5. Made changes, saved a new version
  6. Open the file one day after

The 86MB download only happened in step 1, in all the other steps, the app opened much faster and I didn’t see the download progress bar.

There’s one scenario where you can get a new download every time, but it’s more rare: if you have an old file, it may need a format update. In this case, the iPhone app will ask you if you want to update it or not. If you choose not to update, it will download again the whole file when you open it and choose not to update, but that’s the only known scenario.

Of course, I could be missing something. Here’s a quick video that shows a download from a file I hadn’t opened in my phone compared to the file I tested with, you’ll see it opens quite fast:


Here’s also the file I downloaded in the first video after reopening it

About auto-lock, we’re aware of this and know this needs improvement, but after unlocking the phone the selected artboard was still there.

If possible, can you share with us your iOS and Sketch versions to our email ?

Also, if this problem happens with specific files, a copy of them will be of great help, :pray: